diff --git a/internal/api/grpc/org/v2/integration_test/org_test.go b/internal/api/grpc/org/v2/integration_test/org_test.go
index 96ad7d5fb..9298e63b3 100644
--- a/internal/api/grpc/org/v2/integration_test/org_test.go
+++ b/internal/api/grpc/org/v2/integration_test/org_test.go
@@ -96,6 +96,31 @@ func TestServer_AddOrganization(t *testing.T) {
 				CreatedAdmins:  []*org.AddOrganizationResponse_CreatedAdmin{},
 			},
 		},
+		{
+			name: "no admin, custom organization ID",
+			ctx:  CTX,
+			req: &org.AddOrganizationRequest{
+				Name:           integration.OrganizationName(),
+				OrganizationId: gu.Ptr("custom-organization-ID"),
+			},
+			want: &org.AddOrganizationResponse{
+				OrganizationId: "custom-organization-ID",
+				CreatedAdmins:  []*org.AddOrganizationResponse_CreatedAdmin{},
+			},
+		},
+		{
+			name: "no admin, custom organization ID (precedence over org ID)",
+			ctx:  CTX,
+			req: &org.AddOrganizationRequest{
+				Name:           integration.OrganizationName(),
+				OrganizationId: gu.Ptr("custom-organization-ID2"),
+				OrgId:          gu.Ptr("custom-org-ID"), // will be ignored in favor of OrganizationId
+			},
+			want: &org.AddOrganizationResponse{
+				OrganizationId: "custom-organization-ID2",
+				CreatedAdmins:  []*org.AddOrganizationResponse_CreatedAdmin{},
+			},
+		},
 		{
 			name: "admin with init with userID passed for Human admin",
 			ctx:  CTX,
diff --git a/internal/api/grpc/org/v2/org.go b/internal/api/grpc/org/v2/org.go
index d10315974..b3333be5e 100644
--- a/internal/api/grpc/org/v2/org.go
+++ b/internal/api/grpc/org/v2/org.go
@@ -142,11 +142,15 @@ func addOrganizationRequestToCommand(request *org.AddOrganizationRequest) (*comm
 	if err != nil {
 		return nil, err
 	}
+	id := request.GetOrganizationId()
+	if id == "" {
+		id = request.GetOrgId() //nolint:staticcheck
+	}
 	return &command.OrgSetup{
 		Name:         request.GetName(),
 		CustomDomain: "",
 		Admins:       admins,
-		OrgID:        request.GetOrgId(),
+		OrgID:        id,
 	}, nil
 }
 
diff --git a/internal/api/grpc/org/v2/org_test.go b/internal/api/grpc/org/v2/org_test.go
index 564c5597e..01a692480 100644
--- a/internal/api/grpc/org/v2/org_test.go
+++ b/internal/api/grpc/org/v2/org_test.go
@@ -54,6 +54,37 @@ func Test_addOrganizationRequestToCommand(t *testing.T) {
 				OrgID:        "org-ID",
 			},
 		},
+		{
+			name: "custom organization ID",
+			args: args{
+				request: &org.AddOrganizationRequest{
+					Name:           "custom org ID",
+					OrganizationId: gu.Ptr("organization-ID"),
+				},
+			},
+			want: &command.OrgSetup{
+				Name:         "custom org ID",
+				CustomDomain: "",
+				Admins:       []*command.OrgSetupAdmin{},
+				OrgID:        "organization-ID",
+			},
+		},
+		{
+			name: "custom organization ID (precedence over org ID)",
+			args: args{
+				request: &org.AddOrganizationRequest{
+					Name:           "custom org ID",
+					OrganizationId: gu.Ptr("organization-ID"),
+					OrgId:          gu.Ptr("org-ID"), // will be ignored in favor of OrganizationId
+				},
+			},
+			want: &command.OrgSetup{
+				Name:         "custom org ID",
+				CustomDomain: "",
+				Admins:       []*command.OrgSetupAdmin{},
+				OrgID:        "organization-ID",
+			},
+		},
 		{
 			name: "user ID",
 			args: args{
diff --git a/proto/zitadel/org/v2/org_service.proto b/proto/zitadel/org/v2/org_service.proto
index 0e97e1b37..e4838d5a5 100644
--- a/proto/zitadel/org/v2/org_service.proto
+++ b/proto/zitadel/org/v2/org_service.proto
@@ -577,6 +577,7 @@ message AddOrganizationRequest{
   // which is the recommended way. The generated ID will be returned in the response.
   //
   // Deprecated: use 'organization_id' field instead.
+  // If both org_id and organization_id are set, organization_id will take precedence.
   optional string org_id = 3 [
     deprecated = true,
     (validate.rules).string = {min_len: 1, max_len: 200},