diff --git a/authentik/providers/proxy/models.py b/authentik/providers/proxy/models.py
index a8dee92ba..80db22d49 100644
--- a/authentik/providers/proxy/models.py
+++ b/authentik/providers/proxy/models.py
@@ -138,7 +138,7 @@ class ProxyProvider(OutpostModel, OAuth2Provider):
                 SCOPE_AK_PROXY,
             ]
         )
-        self.property_mappings.set(scopes)
+        self.property_mappings.add(*list(scopes))
         self.redirect_uris = _get_callback_url(self.external_host)
 
     def __str__(self):
diff --git a/web/src/pages/providers/proxy/ProxyProviderForm.ts b/web/src/pages/providers/proxy/ProxyProviderForm.ts
index 000d072b7..c51e99c5a 100644
--- a/web/src/pages/providers/proxy/ProxyProviderForm.ts
+++ b/web/src/pages/providers/proxy/ProxyProviderForm.ts
@@ -14,6 +14,7 @@ import {
     CryptoApi,
     FlowsApi,
     FlowsInstancesListDesignationEnum,
+    PropertymappingsApi,
     ProvidersApi,
     ProxyMode,
     ProxyProvider,
@@ -320,7 +321,7 @@ export class ProxyProviderFormPage extends ModelForm<ProxyProvider, number> {
             </ak-form-element-horizontal>
 
             <ak-form-group>
-                <span slot="header"> ${t`Advanced protocol settings`} </span>
+                <span slot="header">${t`Advanced protocol settings`}</span>
                 <div slot="body" class="pf-c-form">
                     <ak-form-element-horizontal label=${t`Certificate`} name="certificate">
                         <select class="pf-c-form-control">
@@ -347,6 +348,38 @@ export class ProxyProviderFormPage extends ModelForm<ProxyProvider, number> {
                             )}
                         </select>
                     </ak-form-element-horizontal>
+                    <ak-form-element-horizontal label=${t`Scopes`} name="propertyMappings">
+                        <select class="pf-c-form-control" multiple>
+                            ${until(
+                                new PropertymappingsApi(DEFAULT_CONFIG)
+                                    .propertymappingsScopeList({
+                                        ordering: "scope_name",
+                                    })
+                                    .then((scopes) => {
+                                        return scopes.results.filter((scope) => {
+                                            return !scope.managed?.startsWith("goauthentik.io/providers");
+                                        }).map((scope) => {
+                                            const selected = (this.instance?.propertyMappings || []).some((su) => {
+                                                return su == scope.pk;
+                                            });
+                                            return html`<option
+                                                value=${ifDefined(scope.pk)}
+                                                ?selected=${selected}
+                                            >
+                                                ${scope.name}
+                                            </option>`;
+                                        });
+                                    }),
+                                html`<option>${t`Loading...`}</option>`,
+                            )}
+                        </select>
+                        <p class="pf-c-form__helper-text">
+                            ${t`Additional scope mappings, which are passed to the proxy.`}
+                        </p>
+                        <p class="pf-c-form__helper-text">
+                            ${t`Hold control/command to select multiple items.`}
+                        </p>
+                    </ak-form-element-horizontal>
 
                     <ak-form-element-horizontal label=${t`Skip path regex`} name="skipPathRegex">
                         <textarea class="pf-c-form-control">