diff --git a/backend/src/graphql/arg/UpdateUserInfosArgs.ts b/backend/src/graphql/arg/UpdateUserInfosArgs.ts
index 2f9df8dd7..e57d4ec82 100644
--- a/backend/src/graphql/arg/UpdateUserInfosArgs.ts
+++ b/backend/src/graphql/arg/UpdateUserInfosArgs.ts
@@ -8,6 +8,9 @@ export class UpdateUserInfosArgs {
   @Field({ nullable: true })
   lastName?: string
 
+  @Field({ nullable: true })
+  alias?: string
+
   @Field({ nullable: true })
   language?: string
 
diff --git a/backend/src/graphql/resolver/UserResolver.test.ts b/backend/src/graphql/resolver/UserResolver.test.ts
index ddfcf173a..7d71d74b1 100644
--- a/backend/src/graphql/resolver/UserResolver.test.ts
+++ b/backend/src/graphql/resolver/UserResolver.test.ts
@@ -1198,6 +1198,28 @@ describe('UserResolver', () => {
         })
       })
 
+      describe('alias', () => {
+        beforeEach(() => {
+          jest.clearAllMocks()
+        })
+
+        describe('valid alias', () => {
+          it('updates the user in DB', async () => {
+            await mutate({
+              mutation: updateUserInfos,
+              variables: {
+                alias: 'bibi_Bloxberg',
+              },
+            })
+            await expect(User.findOne()).resolves.toEqual(
+              expect.objectContaining({
+                alias: 'bibi_Bloxberg',
+              }),
+            )
+          })
+        })
+      })
+
       describe('language is not valid', () => {
         it('throws an error', async () => {
           jest.clearAllMocks()
diff --git a/backend/src/graphql/resolver/UserResolver.ts b/backend/src/graphql/resolver/UserResolver.ts
index ca38ae769..0afbfcc5a 100644
--- a/backend/src/graphql/resolver/UserResolver.ts
+++ b/backend/src/graphql/resolver/UserResolver.ts
@@ -73,6 +73,7 @@ import { getTimeDurationObject, printTimeDuration } from '@/util/time'
 import { FULL_CREATION_AVAILABLE } from './const/const'
 import { getUserCreations } from './util/creations'
 import { findUserByIdentifier } from './util/findUserByIdentifier'
+import { validateAlias } from './util/validateAlias'
 
 // eslint-disable-next-line @typescript-eslint/no-var-requires, import/no-commonjs
 const random = require('random-bigint')
@@ -504,6 +505,7 @@ export class UserResolver {
     {
       firstName,
       lastName,
+      alias,
       language,
       password,
       passwordNew,
@@ -523,6 +525,10 @@ export class UserResolver {
       user.lastName = lastName
     }
 
+    if (alias && (await validateAlias(alias))) {
+      user.alias = alias
+    }
+
     if (language) {
       if (!isLanguage(language)) {
         throw new LogError('Given language is not a valid language', language)
diff --git a/backend/src/graphql/resolver/util/validateAlias.test.ts b/backend/src/graphql/resolver/util/validateAlias.test.ts
new file mode 100644
index 000000000..0cb790edb
--- /dev/null
+++ b/backend/src/graphql/resolver/util/validateAlias.test.ts
@@ -0,0 +1,125 @@
+import { Connection } from '@dbTools/typeorm'
+import { User } from '@entity/User'
+import { ApolloServerTestClient } from 'apollo-server-testing'
+
+import { testEnvironment, cleanDB } from '@test/helpers'
+import { logger, i18n as localization } from '@test/testSetup'
+
+import { userFactory } from '@/seeds/factory/user'
+import { bibiBloxberg } from '@/seeds/users/bibi-bloxberg'
+
+import { validateAlias } from './validateAlias'
+
+let con: Connection
+let testEnv: {
+  mutate: ApolloServerTestClient['mutate']
+  query: ApolloServerTestClient['query']
+  con: Connection
+}
+
+beforeAll(async () => {
+  testEnv = await testEnvironment(logger, localization)
+  con = testEnv.con
+  await cleanDB()
+})
+
+afterAll(async () => {
+  await cleanDB()
+  await con.close()
+})
+
+describe('validate alias', () => {
+  beforeAll(() => {
+    jest.clearAllMocks()
+  })
+
+  describe('alias too short', () => {
+    it('throws and logs an error', async () => {
+      await expect(validateAlias('Bi')).rejects.toEqual(new Error('Given alias is too short'))
+      expect(logger.error).toBeCalledWith('Given alias is too short', 'Bi')
+    })
+  })
+
+  describe('alias too long', () => {
+    it('throws and logs an error', async () => {
+      await expect(validateAlias('BibiBloxbergHexHexHex')).rejects.toEqual(
+        new Error('Given alias is too long'),
+      )
+      expect(logger.error).toBeCalledWith('Given alias is too long', 'BibiBloxbergHexHexHex')
+    })
+  })
+
+  describe('alias contains invalid characters', () => {
+    it('throws and logs an error', async () => {
+      await expect(validateAlias('Bibi.Bloxberg')).rejects.toEqual(
+        new Error('Invalid characters in alias'),
+      )
+      expect(logger.error).toBeCalledWith('Invalid characters in alias', 'Bibi.Bloxberg')
+    })
+  })
+
+  describe('alias is a reserved word', () => {
+    it('throws and logs an error', async () => {
+      await expect(validateAlias('admin')).rejects.toEqual(new Error('Alias is not allowed'))
+      expect(logger.error).toBeCalledWith('Alias is not allowed', 'admin')
+    })
+  })
+
+  describe('alias is a reserved word with uppercase characters', () => {
+    it('throws and logs an error', async () => {
+      await expect(validateAlias('Admin')).rejects.toEqual(new Error('Alias is not allowed'))
+      expect(logger.error).toBeCalledWith('Alias is not allowed', 'Admin')
+    })
+  })
+
+  describe('hyphens and underscore', () => {
+    describe('alias starts with underscore', () => {
+      it('throws and logs an error', async () => {
+        await expect(validateAlias('_bibi')).rejects.toEqual(
+          new Error('Invalid characters in alias'),
+        )
+        expect(logger.error).toBeCalledWith('Invalid characters in alias', '_bibi')
+      })
+    })
+
+    describe('alias contains two following hyphens', () => {
+      it('throws and logs an error', async () => {
+        await expect(validateAlias('bi--bi')).rejects.toEqual(
+          new Error('Invalid characters in alias'),
+        )
+        expect(logger.error).toBeCalledWith('Invalid characters in alias', 'bi--bi')
+      })
+    })
+  })
+
+  describe('test against existing alias in database', () => {
+    beforeAll(async () => {
+      const bibi = await userFactory(testEnv, bibiBloxberg)
+      const user = await User.findOne({ id: bibi.id })
+      if (user) {
+        user.alias = 'b-b'
+        await user.save()
+      }
+    })
+
+    describe('alias exists in database', () => {
+      it('throws and logs an error', async () => {
+        await expect(validateAlias('b-b')).rejects.toEqual(new Error('Alias already in use'))
+        expect(logger.error).toBeCalledWith('Alias already in use', 'b-b')
+      })
+    })
+
+    describe('alias exists in database with in lower-case', () => {
+      it('throws and logs an error', async () => {
+        await expect(validateAlias('b-B')).rejects.toEqual(new Error('Alias already in use'))
+        expect(logger.error).toBeCalledWith('Alias already in use', 'b-B')
+      })
+    })
+
+    describe('valid alias', () => {
+      it('resolves to true', async () => {
+        await expect(validateAlias('bibi')).resolves.toEqual(true)
+      })
+    })
+  })
+})
diff --git a/backend/src/graphql/resolver/util/validateAlias.ts b/backend/src/graphql/resolver/util/validateAlias.ts
new file mode 100644
index 000000000..dcea7824c
--- /dev/null
+++ b/backend/src/graphql/resolver/util/validateAlias.ts
@@ -0,0 +1,38 @@
+import { Raw } from '@dbTools/typeorm'
+import { User as DbUser } from '@entity/User'
+
+import { LogError } from '@/server/LogError'
+
+const reservedAlias = [
+  'admin',
+  'email',
+  'gast',
+  'gdd',
+  'gradido',
+  'guest',
+  'home',
+  'root',
+  'support',
+  'temp',
+  'tmp',
+  'tmp',
+  'user',
+  'usr',
+  'var',
+]
+
+export const validateAlias = async (alias: string): Promise<boolean> => {
+  if (alias.length < 3) throw new LogError('Given alias is too short', alias)
+  if (alias.length > 20) throw new LogError('Given alias is too long', alias)
+  /* eslint-disable-next-line security/detect-unsafe-regex */
+  if (!alias.match(/^[0-9A-Za-z]([_-]?[A-Za-z0-9])+$/))
+    throw new LogError('Invalid characters in alias', alias)
+  if (reservedAlias.includes(alias.toLowerCase())) throw new LogError('Alias is not allowed', alias)
+  const aliasInUse = await DbUser.find({
+    where: { alias: Raw((a) => `LOWER(${a}) = "${alias.toLowerCase()}"`) },
+  })
+  if (aliasInUse.length !== 0) {
+    throw new LogError('Alias already in use', alias)
+  }
+  return true
+}
diff --git a/backend/src/seeds/graphql/mutations.ts b/backend/src/seeds/graphql/mutations.ts
index 2dfe96766..22e0b1b09 100644
--- a/backend/src/seeds/graphql/mutations.ts
+++ b/backend/src/seeds/graphql/mutations.ts
@@ -28,6 +28,7 @@ export const updateUserInfos = gql`
   mutation (
     $firstName: String
     $lastName: String
+    $alias: String
     $password: String
     $passwordNew: String
     $locale: String
@@ -37,6 +38,7 @@ export const updateUserInfos = gql`
     updateUserInfos(
       firstName: $firstName
       lastName: $lastName
+      alias: $alias
       password: $password
       passwordNew: $passwordNew
       language: $locale