diff --git a/src/modules/authentication/authentication.module.ts b/src/modules/authentication/authentication.module.ts
index c319fa3..539f55b 100644
--- a/src/modules/authentication/authentication.module.ts
+++ b/src/modules/authentication/authentication.module.ts
@@ -23,6 +23,8 @@ import { UpdateUsernameGrpcController } from './interface/grpc-controllers/updat
 import { UpdateUsernameService } from './core/application/commands/update-username/update-username.service';
 import { UpdatePasswordGrpcController } from './interface/grpc-controllers/update-password.grpc.controller';
 import { UpdatePasswordService } from './core/application/commands/update-password/update-password.service';
+import { ValidateAuthenticationGrpcController } from './interface/grpc-controllers/validate-authentication.grpc.controller';
+import { ValidateAuthenticationQueryHandler } from './core/application/queries/validate-authentication/validate-authentication.query-handler';
 
 const grpcControllers = [
   CreateAuthenticationGrpcController,
@@ -31,6 +33,7 @@ const grpcControllers = [
   UpdateUsernameGrpcController,
   DeleteUsernameGrpcController,
   UpdatePasswordGrpcController,
+  ValidateAuthenticationGrpcController,
 ];
 
 const commandHandlers: Provider[] = [
@@ -42,6 +45,8 @@ const commandHandlers: Provider[] = [
   UpdatePasswordService,
 ];
 
+const queryHandlers: Provider[] = [ValidateAuthenticationQueryHandler];
+
 const mappers: Provider[] = [AuthenticationMapper, UsernameMapper];
 
 const repositories: Provider[] = [
@@ -69,6 +74,7 @@ const orms: Provider[] = [PrismaService];
   controllers: [...grpcControllers],
   providers: [
     ...commandHandlers,
+    ...queryHandlers,
     ...mappers,
     ...repositories,
     ...messageBrokers,
diff --git a/src/modules/authentication/core/application/ports/username.repository.port.ts b/src/modules/authentication/core/application/ports/username.repository.port.ts
index 14ce69b..9188472 100644
--- a/src/modules/authentication/core/application/ports/username.repository.port.ts
+++ b/src/modules/authentication/core/application/ports/username.repository.port.ts
@@ -4,5 +4,6 @@ import { Type } from '../../domain/username.types';
 
 export type UsernameRepositoryPort = RepositoryPort<UsernameEntity> & {
   findByType(userId: string, type: Type): Promise<UsernameEntity>;
+  findByName(name: string): Promise<UsernameEntity>;
   updateUsername(oldName: string, entity: UsernameEntity): Promise<void>;
 };
diff --git a/src/modules/authentication/core/application/queries/validate-authentication/validate-authentication.query-handler.ts b/src/modules/authentication/core/application/queries/validate-authentication/validate-authentication.query-handler.ts
new file mode 100644
index 0000000..88aa703
--- /dev/null
+++ b/src/modules/authentication/core/application/queries/validate-authentication/validate-authentication.query-handler.ts
@@ -0,0 +1,50 @@
+import { IQueryHandler, QueryHandler } from '@nestjs/cqrs';
+import { Inject, UnauthorizedException } from '@nestjs/common';
+import { ValidateAuthenticationQuery } from './validate-authentication.query';
+import {
+  AUTHENTICATION_REPOSITORY,
+  USERNAME_REPOSITORY,
+} from '@modules/authentication/authentication.di-tokens';
+import { AuthenticationRepositoryPort } from '../../ports/authentication.repository.port';
+import { UsernameRepositoryPort } from '../../ports/username.repository.port';
+import { AuthenticationEntity } from '@modules/authentication/core/domain/authentication.entity';
+import { UsernameEntity } from '@modules/authentication/core/domain/username.entity';
+import { AggregateID, NotFoundException } from '@mobicoop/ddd-library';
+
+@QueryHandler(ValidateAuthenticationQuery)
+export class ValidateAuthenticationQueryHandler implements IQueryHandler {
+  constructor(
+    @Inject(AUTHENTICATION_REPOSITORY)
+    private readonly authenticationRepository: AuthenticationRepositoryPort,
+    @Inject(USERNAME_REPOSITORY)
+    private readonly usernameRepository: UsernameRepositoryPort,
+  ) {}
+
+  execute = async (
+    query: ValidateAuthenticationQuery,
+  ): Promise<AggregateID> => {
+    let usernameEntity: UsernameEntity;
+    try {
+      usernameEntity = await this.usernameRepository.findByName(query.name);
+    } catch (e) {
+      throw new NotFoundException();
+    }
+    let authenticationEntity: AuthenticationEntity;
+    try {
+      authenticationEntity = await this.authenticationRepository.findOneById(
+        usernameEntity.getProps().userId,
+      );
+    } catch (e) {
+      throw new NotFoundException();
+    }
+    try {
+      const isAuthenticated = await authenticationEntity.authenticate(
+        query.password,
+      );
+      if (isAuthenticated) return authenticationEntity.id;
+      throw new UnauthorizedException();
+    } catch (e) {
+      throw new UnauthorizedException();
+    }
+  };
+}
diff --git a/src/modules/authentication/core/application/queries/validate-authentication/validate-authentication.query.ts b/src/modules/authentication/core/application/queries/validate-authentication/validate-authentication.query.ts
new file mode 100644
index 0000000..f979a9e
--- /dev/null
+++ b/src/modules/authentication/core/application/queries/validate-authentication/validate-authentication.query.ts
@@ -0,0 +1,12 @@
+import { QueryBase } from '@mobicoop/ddd-library';
+
+export class ValidateAuthenticationQuery extends QueryBase {
+  readonly name: string;
+  readonly password: string;
+
+  constructor(name: string, password: string) {
+    super();
+    this.name = name;
+    this.password = password;
+  }
+}
diff --git a/src/modules/authentication/core/domain/authentication.entity.ts b/src/modules/authentication/core/domain/authentication.entity.ts
index 6b900af..184a0af 100644
--- a/src/modules/authentication/core/domain/authentication.entity.ts
+++ b/src/modules/authentication/core/domain/authentication.entity.ts
@@ -47,6 +47,9 @@ export class AuthenticationEntity extends AggregateRoot<AuthenticationProps> {
     );
   }
 
+  authenticate = async (password: string): Promise<boolean> =>
+    await bcrypt.compare(password, this.props.password);
+
   validate(): void {
     // entity business rules validation to protect it's invariant before saving entity to a database
   }
diff --git a/src/modules/authentication/infrastructure/username.repository.ts b/src/modules/authentication/infrastructure/username.repository.ts
index 22e5148..9342bdd 100644
--- a/src/modules/authentication/infrastructure/username.repository.ts
+++ b/src/modules/authentication/infrastructure/username.repository.ts
@@ -54,6 +54,11 @@ export class UsernameRepository
       type,
     });
 
+  findByName = async (name: string): Promise<UsernameEntity> =>
+    this.findOne({
+      username: name,
+    });
+
   updateUsername = async (
     oldName: string,
     entity: UsernameEntity,
diff --git a/src/modules/authentication/interface/grpc-controllers/authentication.proto b/src/modules/authentication/interface/grpc-controllers/authentication.proto
index 87d04f7..604b09c 100644
--- a/src/modules/authentication/interface/grpc-controllers/authentication.proto
+++ b/src/modules/authentication/interface/grpc-controllers/authentication.proto
@@ -3,7 +3,7 @@ syntax = "proto3";
 package authentication;
 
 service AuthenticationService {
-  rpc Validate(AuthenticationByUsernamePassword) returns (Id);
+  rpc Validate(AuthenticationByNamePassword) returns (Id);
   rpc Create(Authentication) returns (Id);
   rpc AddUsername(Username) returns (Id);
   rpc UpdatePassword(Password) returns (Id);
@@ -12,8 +12,8 @@ service AuthenticationService {
   rpc Delete(UserId) returns (Empty);
 }
 
-message AuthenticationByUsernamePassword {
-  string username = 1;
+message AuthenticationByNamePassword {
+  string name = 1;
   string password = 2;
 }
 
diff --git a/src/modules/authentication/interface/grpc-controllers/dtos/validate-authentication.request.dto.ts b/src/modules/authentication/interface/grpc-controllers/dtos/validate-authentication.request.dto.ts
new file mode 100644
index 0000000..6637cb8
--- /dev/null
+++ b/src/modules/authentication/interface/grpc-controllers/dtos/validate-authentication.request.dto.ts
@@ -0,0 +1,11 @@
+import { IsNotEmpty, IsString } from 'class-validator';
+
+export class ValidateAuthenticationRequestDto {
+  @IsString()
+  @IsNotEmpty()
+  name: string;
+
+  @IsString()
+  @IsNotEmpty()
+  password: string;
+}
diff --git a/src/modules/authentication/interface/grpc-controllers/validate-authentication.grpc.controller.ts b/src/modules/authentication/interface/grpc-controllers/validate-authentication.grpc.controller.ts
new file mode 100644
index 0000000..71f0673
--- /dev/null
+++ b/src/modules/authentication/interface/grpc-controllers/validate-authentication.grpc.controller.ts
@@ -0,0 +1,37 @@
+import {
+  AggregateID,
+  IdResponse,
+  RpcExceptionCode,
+  RpcValidationPipe,
+} from '@mobicoop/ddd-library';
+import { Controller, UsePipes } from '@nestjs/common';
+import { QueryBus } from '@nestjs/cqrs';
+import { GrpcMethod, RpcException } from '@nestjs/microservices';
+import { ValidateAuthenticationRequestDto } from './dtos/validate-authentication.request.dto';
+import { ValidateAuthenticationQuery } from '@modules/authentication/core/application/queries/validate-authentication/validate-authentication.query';
+
+@UsePipes(
+  new RpcValidationPipe({
+    whitelist: true,
+    forbidUnknownValues: false,
+  }),
+)
+@Controller()
+export class ValidateAuthenticationGrpcController {
+  constructor(private readonly queryBus: QueryBus) {}
+
+  @GrpcMethod('AuthenticationService', 'Validate')
+  async validate(data: ValidateAuthenticationRequestDto): Promise<IdResponse> {
+    try {
+      const aggregateID: AggregateID = await this.queryBus.execute(
+        new ValidateAuthenticationQuery(data.name, data.password),
+      );
+      return new IdResponse(aggregateID);
+    } catch (error: any) {
+      throw new RpcException({
+        code: RpcExceptionCode.PERMISSION_DENIED,
+        message: 'Permission denied',
+      });
+    }
+  }
+}
diff --git a/src/modules/authentication/tests/unit/core/authentication.entity.spec.ts b/src/modules/authentication/tests/unit/core/authentication.entity.spec.ts
index 1d5f7dd..761beb7 100644
--- a/src/modules/authentication/tests/unit/core/authentication.entity.spec.ts
+++ b/src/modules/authentication/tests/unit/core/authentication.entity.spec.ts
@@ -76,3 +76,21 @@ describe('Authentication password update', () => {
     expect(authenticationEntity.getProps().password).not.toBe(oldPassword);
   });
 });
+describe('Authentication password validation', () => {
+  it('should validate a valid password', async () => {
+    const authenticationEntity: AuthenticationEntity =
+      await AuthenticationEntity.create(createAuthenticationProps);
+    const result: boolean = await authenticationEntity.authenticate(
+      'somePassword',
+    );
+    expect(result).toBeTruthy();
+  });
+  it('should not validate an invalid password', async () => {
+    const authenticationEntity: AuthenticationEntity =
+      await AuthenticationEntity.create(createAuthenticationProps);
+    const result: boolean = await authenticationEntity.authenticate(
+      'someWrongPassword',
+    );
+    expect(result).toBeFalsy();
+  });
+});
diff --git a/src/modules/authentication/tests/unit/core/validate-authentication.query-handler.spec.ts b/src/modules/authentication/tests/unit/core/validate-authentication.query-handler.spec.ts
new file mode 100644
index 0000000..dd71fe3
--- /dev/null
+++ b/src/modules/authentication/tests/unit/core/validate-authentication.query-handler.spec.ts
@@ -0,0 +1,120 @@
+import { AggregateID, NotFoundException } from '@mobicoop/ddd-library';
+import {
+  AUTHENTICATION_REPOSITORY,
+  USERNAME_REPOSITORY,
+} from '@modules/authentication/authentication.di-tokens';
+import { ValidateAuthenticationQuery } from '@modules/authentication/core/application/queries/validate-authentication/validate-authentication.query';
+import { ValidateAuthenticationQueryHandler } from '@modules/authentication/core/application/queries/validate-authentication/validate-authentication.query-handler';
+import { UnauthorizedException } from '@nestjs/common';
+
+import { Test, TestingModule } from '@nestjs/testing';
+
+const validName = 'john.doe@email.com';
+const furtherInvalidName = 'validNameButInvalidAuthenticationForSomeReason';
+const validUserId = '165192d4-398a-4469-a16b-98c02cc6f531';
+const invalidUserId = 'b3b75798-7104-4151-adab-11fe16e32d85';
+const validPassword = 'V@l1dP@$$w0rd';
+const invalidPassword = '1nV@l1dP@$$w0rd';
+
+const mockUsernameRepository = {
+  findByName: jest.fn().mockImplementation((name: string) => {
+    if (name == validName) {
+      return {
+        getProps: jest.fn().mockImplementation(() => ({
+          userId: validUserId,
+        })),
+      };
+    }
+    if (name == furtherInvalidName) {
+      return {
+        getProps: jest.fn().mockImplementation(() => ({
+          userId: invalidUserId,
+        })),
+      };
+    }
+    throw new Error();
+  }),
+};
+
+const mockAuthenticationEntity = {
+  id: validUserId,
+  authenticate: jest
+    .fn()
+    .mockImplementation((password: string) => password === validPassword),
+};
+
+const mockAuthenticationRepository = {
+  findOneById: jest.fn().mockImplementation((id: string) => {
+    if (id === validUserId) return mockAuthenticationEntity;
+    throw new Error();
+  }),
+};
+
+describe('Validate Authentication Query Handler', () => {
+  let validateAuthenticationQueryHandler: ValidateAuthenticationQueryHandler;
+
+  beforeAll(async () => {
+    const module: TestingModule = await Test.createTestingModule({
+      providers: [
+        {
+          provide: AUTHENTICATION_REPOSITORY,
+          useValue: mockAuthenticationRepository,
+        },
+        {
+          provide: USERNAME_REPOSITORY,
+          useValue: mockUsernameRepository,
+        },
+        ValidateAuthenticationQueryHandler,
+      ],
+    }).compile();
+
+    validateAuthenticationQueryHandler =
+      module.get<ValidateAuthenticationQueryHandler>(
+        ValidateAuthenticationQueryHandler,
+      );
+  });
+
+  it('should be defined', () => {
+    expect(validateAuthenticationQueryHandler).toBeDefined();
+  });
+
+  describe('execution', () => {
+    it('should validate an authentication query', async () => {
+      const validateAuthenticationQuery = new ValidateAuthenticationQuery(
+        validName,
+        validPassword,
+      );
+      const id: AggregateID = await validateAuthenticationQueryHandler.execute(
+        validateAuthenticationQuery,
+      );
+      expect(id).toBe(validUserId);
+    });
+    it('should not validate an authentication query if username is invalid', async () => {
+      const validateAuthenticationQuery = new ValidateAuthenticationQuery(
+        'invalidName',
+        validPassword,
+      );
+      await expect(
+        validateAuthenticationQueryHandler.execute(validateAuthenticationQuery),
+      ).rejects.toBeInstanceOf(NotFoundException);
+    });
+    it('should not validate an authentication query if authentication is not found', async () => {
+      const validateAuthenticationQuery = new ValidateAuthenticationQuery(
+        furtherInvalidName,
+        validPassword,
+      );
+      await expect(
+        validateAuthenticationQueryHandler.execute(validateAuthenticationQuery),
+      ).rejects.toBeInstanceOf(NotFoundException);
+    });
+    it('should not validate a failing authentication query', async () => {
+      const validateAuthenticationQuery = new ValidateAuthenticationQuery(
+        validName,
+        invalidPassword,
+      );
+      await expect(
+        validateAuthenticationQueryHandler.execute(validateAuthenticationQuery),
+      ).rejects.toBeInstanceOf(UnauthorizedException);
+    });
+  });
+});
diff --git a/src/modules/authentication/tests/unit/infrastructure/username.repository.spec.ts b/src/modules/authentication/tests/unit/infrastructure/username.repository.spec.ts
index 23842f9..a9b08b9 100644
--- a/src/modules/authentication/tests/unit/infrastructure/username.repository.spec.ts
+++ b/src/modules/authentication/tests/unit/infrastructure/username.repository.spec.ts
@@ -59,6 +59,11 @@ describe('Username repository', () => {
       mockMessagePublisher,
     );
   });
+
+  afterEach(async () => {
+    jest.clearAllMocks();
+  });
+
   it('should be defined', () => {
     expect(usernameRepository).toBeDefined();
   });
@@ -75,6 +80,17 @@ describe('Username repository', () => {
     });
     expect(username.getProps().name).toBe('john.doe@email.com');
   });
+  it('should find a username by its name', async () => {
+    jest.spyOn(usernameRepository, 'findOne');
+    const username: UsernameEntity = await usernameRepository.findByName(
+      'john.doe@email.com',
+    );
+    expect(usernameRepository.findOne).toHaveBeenCalledTimes(1);
+    expect(usernameRepository.findOne).toHaveBeenCalledWith({
+      username: 'john.doe@email.com',
+    });
+    expect(username.getProps().name).toBe('john.doe@email.com');
+  });
   it('should update a username', async () => {
     jest.spyOn(usernameRepository, 'updateWhere');
     const usernameToUpdate: UsernameEntity = await UsernameEntity.create({
diff --git a/src/modules/authentication/tests/unit/interface/validate-authentication.grpc.controller.spec.ts b/src/modules/authentication/tests/unit/interface/validate-authentication.grpc.controller.spec.ts
new file mode 100644
index 0000000..e6babb3
--- /dev/null
+++ b/src/modules/authentication/tests/unit/interface/validate-authentication.grpc.controller.spec.ts
@@ -0,0 +1,75 @@
+import { IdResponse } from '@mobicoop/ddd-library';
+import { RpcExceptionCode } from '@mobicoop/ddd-library';
+import { ValidateAuthenticationRequestDto } from '@modules/authentication/interface/grpc-controllers/dtos/validate-authentication.request.dto';
+import { ValidateAuthenticationGrpcController } from '@modules/authentication/interface/grpc-controllers/validate-authentication.grpc.controller';
+import { QueryBus } from '@nestjs/cqrs';
+import { RpcException } from '@nestjs/microservices';
+import { Test, TestingModule } from '@nestjs/testing';
+
+const validateAuthenticationRequest: ValidateAuthenticationRequestDto = {
+  password: 'John123',
+  name: 'john.doe@email.com',
+};
+
+const mockQueryBus = {
+  execute: jest
+    .fn()
+    .mockImplementationOnce(() => '78153e03-4861-4f58-a705-88526efee53b')
+    .mockImplementationOnce(() => {
+      throw new Error();
+    }),
+};
+
+describe('Validate Authentication Grpc Controller', () => {
+  let validateAuthenticationGrpcController: ValidateAuthenticationGrpcController;
+
+  beforeAll(async () => {
+    const module: TestingModule = await Test.createTestingModule({
+      providers: [
+        {
+          provide: QueryBus,
+          useValue: mockQueryBus,
+        },
+        ValidateAuthenticationGrpcController,
+      ],
+    }).compile();
+
+    validateAuthenticationGrpcController =
+      module.get<ValidateAuthenticationGrpcController>(
+        ValidateAuthenticationGrpcController,
+      );
+  });
+
+  afterEach(async () => {
+    jest.clearAllMocks();
+  });
+
+  it('should be defined', () => {
+    expect(validateAuthenticationGrpcController).toBeDefined();
+  });
+
+  it('should validate an authentication', async () => {
+    jest.spyOn(mockQueryBus, 'execute');
+    const result: IdResponse =
+      await validateAuthenticationGrpcController.validate(
+        validateAuthenticationRequest,
+      );
+    expect(result).toBeInstanceOf(IdResponse);
+    expect(result.id).toBe('78153e03-4861-4f58-a705-88526efee53b');
+    expect(mockQueryBus.execute).toHaveBeenCalledTimes(1);
+  });
+
+  it('should throw a dedicated RpcException if authentication fails', async () => {
+    jest.spyOn(mockQueryBus, 'execute');
+    expect.assertions(3);
+    try {
+      await validateAuthenticationGrpcController.validate(
+        validateAuthenticationRequest,
+      );
+    } catch (e: any) {
+      expect(e).toBeInstanceOf(RpcException);
+      expect(e.error.code).toBe(RpcExceptionCode.PERMISSION_DENIED);
+    }
+    expect(mockQueryBus.execute).toHaveBeenCalledTimes(1);
+  });
+});