diff --git a/src/Turnierplan.App/Client/src/app/portal/components/rbac-offcanvas/rbac-offcanvas.component.html b/src/Turnierplan.App/Client/src/app/portal/components/rbac-offcanvas/rbac-offcanvas.component.html
index 758ef58d..c1a85dfd 100644
--- a/src/Turnierplan.App/Client/src/app/portal/components/rbac-offcanvas/rbac-offcanvas.component.html
+++ b/src/Turnierplan.App/Client/src/app/portal/components/rbac-offcanvas/rbac-offcanvas.component.html
@@ -41,7 +41,7 @@
                     }
                   </div>
                   @if (assignment.isInherited) {
-                    <div class="text-primary d-flex gap-2">
+                    <div class="text-primary d-flex gap-1 small">
                       <i class="bi bi-info-circle" [ngbTooltip]="'Portal.RbacManagement.InheritedTooltip' | translate"></i>
                       <span translate="Portal.RbacManagement.Inherited"></span>
                       <a
diff --git a/src/Turnierplan.App/Client/src/app/portal/components/rbac-principal/rbac-principal.component.html b/src/Turnierplan.App/Client/src/app/portal/components/rbac-principal/rbac-principal.component.html
index d3d7f345..6696266a 100644
--- a/src/Turnierplan.App/Client/src/app/portal/components/rbac-principal/rbac-principal.component.html
+++ b/src/Turnierplan.App/Client/src/app/portal/components/rbac-principal/rbac-principal.component.html
@@ -6,5 +6,4 @@
     <i class="bi bi-person" [ngbTooltip]="'Portal.RbacManagement.PrincipalKind.User' | translate"></i>
   }
 }
-<!-- TODO: Resolve ApiKey/User name -->
-<span class="ms-1">{{ principal.principalId }}</span>
+<span class="ms-2">{{ displayName$ | async }}</span>
diff --git a/src/Turnierplan.App/Client/src/app/portal/components/rbac-principal/rbac-principal.component.ts b/src/Turnierplan.App/Client/src/app/portal/components/rbac-principal/rbac-principal.component.ts
index 63a450ba..4cdba553 100644
--- a/src/Turnierplan.App/Client/src/app/portal/components/rbac-principal/rbac-principal.component.ts
+++ b/src/Turnierplan.App/Client/src/app/portal/components/rbac-principal/rbac-principal.component.ts
@@ -1,14 +1,33 @@
-import { Component, Input } from '@angular/core';
+import { Component, Input, OnInit } from '@angular/core';
 import { PrincipalDto, PrincipalKind } from '../../../api';
+import { PrincipalsService } from '../../../api/services/principals.service';
+import { catchError, Observable, of } from 'rxjs';
+import { map } from 'rxjs/operators';
 
 @Component({
   selector: 'tp-rbac-principal',
   standalone: false,
   templateUrl: './rbac-principal.component.html'
 })
-export class RbacPrincipalComponent {
+export class RbacPrincipalComponent implements OnInit {
   protected readonly PrincipalKind = PrincipalKind;
 
+  protected displayName$?: Observable<string>;
+
   @Input()
   public principal!: PrincipalDto;
+
+  constructor(private readonly principalsService: PrincipalsService) {}
+
+  public ngOnInit(): void {
+    this.displayName$ = this.principalsService
+      .getPrincipalName({
+        principalKind: this.principal.kind,
+        principalId: this.principal.principalId
+      })
+      .pipe(
+        map((result) => result.name),
+        catchError(() => of(this.principal.principalId))
+      );
+  }
 }
diff --git a/src/Turnierplan.App/Endpoints/Principals/GetPrincipalNameEndpoint.cs b/src/Turnierplan.App/Endpoints/Principals/GetPrincipalNameEndpoint.cs
new file mode 100644
index 00000000..256d0a62
--- /dev/null
+++ b/src/Turnierplan.App/Endpoints/Principals/GetPrincipalNameEndpoint.cs
@@ -0,0 +1,44 @@
+using Microsoft.AspNetCore.Mvc;
+using Turnierplan.Core.ApiKey;
+using Turnierplan.Core.RoleAssignment;
+using Turnierplan.Core.User;
+
+namespace Turnierplan.App.Endpoints.Principals;
+
+internal sealed class GetPrincipalNameEndpoint : EndpointBase<GetPrincipalNameEndpoint.GetPrincipalNameEndpointResponse>
+{
+    protected override HttpMethod Method => HttpMethod.Get;
+
+    protected override string Route => "/api/principals/name";
+
+    protected override Delegate Handler => Handle;
+
+    private static async Task<IResult> Handle(
+        [FromQuery] PrincipalKind principalKind,
+        [FromQuery] Guid principalId,
+        IApiKeyRepository apiKeyRepository,
+        IUserRepository userRepository)
+    {
+        string? name;
+
+        switch (principalKind)
+        {
+            case PrincipalKind.ApiKey:
+                var apiKey = await apiKeyRepository.GetByPrincipalIdAsync(principalId).ConfigureAwait(false);
+                name = apiKey?.Name;
+                break;
+            case PrincipalKind.User:
+                var user = await userRepository.GetByPrincipalIdAsync(principalId).ConfigureAwait(false);
+                name = user?.Name;
+                break;
+            default:
+                return Results.BadRequest("Invalid principal kind specified.");
+        }
+
+        return name is not null
+            ? Results.Ok(new GetPrincipalNameEndpointResponse(name))
+            : Results.NotFound();
+    }
+
+    public sealed record GetPrincipalNameEndpointResponse(string Name);
+}
diff --git a/src/Turnierplan.Core/ApiKey/IApiKeyRepository.cs b/src/Turnierplan.Core/ApiKey/IApiKeyRepository.cs
index 6bd5c7d5..b468ece4 100644
--- a/src/Turnierplan.Core/ApiKey/IApiKeyRepository.cs
+++ b/src/Turnierplan.Core/ApiKey/IApiKeyRepository.cs
@@ -4,5 +4,7 @@ namespace Turnierplan.Core.ApiKey;
 
 public interface IApiKeyRepository : IRepositoryWithPublicId<ApiKey, long>
 {
+    Task<ApiKey?> GetByPrincipalIdAsync(Guid id);
+
     Task<List<ApiKeyRequest>> GetRequestsInTimeRange(ApiKey apiKey, DateTime start, DateTime end);
 }
diff --git a/src/Turnierplan.Core/User/IUserRepository.cs b/src/Turnierplan.Core/User/IUserRepository.cs
index 7b94f56a..e3703563 100644
--- a/src/Turnierplan.Core/User/IUserRepository.cs
+++ b/src/Turnierplan.Core/User/IUserRepository.cs
@@ -8,5 +8,7 @@ public interface IUserRepository : IRepository<User, Guid>
 
     Task<User?> GetByIdAsync(Guid id);
 
+    Task<User?> GetByPrincipalIdAsync(Guid id);
+
     Task<User?> GetByEmailAsync(string email);
 }
diff --git a/src/Turnierplan.Dal/Repositories/ApiKeyRepository.cs b/src/Turnierplan.Dal/Repositories/ApiKeyRepository.cs
index 608f65d9..ff3d68c1 100644
--- a/src/Turnierplan.Dal/Repositories/ApiKeyRepository.cs
+++ b/src/Turnierplan.Dal/Repositories/ApiKeyRepository.cs
@@ -23,6 +23,11 @@ public ApiKeyRepository(TurnierplanContext context)
             .FirstOrDefaultAsync();
     }
 
+    public Task<ApiKey?> GetByPrincipalIdAsync(Guid id)
+    {
+        return DbSet.Where(x => x.PrincipalId == id).FirstOrDefaultAsync();
+    }
+
     public Task<List<ApiKeyRequest>> GetRequestsInTimeRange(ApiKey apiKey, DateTime start, DateTime end)
     {
         return _requests.Where(x => x.ApiKey == apiKey && x.Timestamp >= start && x.Timestamp <= end)
diff --git a/src/Turnierplan.Dal/Repositories/UserRepository.cs b/src/Turnierplan.Dal/Repositories/UserRepository.cs
index 3fb65403..d4b4deac 100644
--- a/src/Turnierplan.Dal/Repositories/UserRepository.cs
+++ b/src/Turnierplan.Dal/Repositories/UserRepository.cs
@@ -16,6 +16,11 @@ public Task<List<User>> GetAllUsers()
         return DbSet.Where(x => x.Id.Equals(id)).FirstOrDefaultAsync();
     }
 
+    public Task<User?> GetByPrincipalIdAsync(Guid id)
+    {
+        return DbSet.Where(x => x.PrincipalId == id).FirstOrDefaultAsync();
+    }
+
     public Task<User?> GetByEmailAsync(string email)
     {
         var normalizedEMail = User.NormalizeEmail(email);