diff --git a/lib/mv_web/live/member_live/show.ex b/lib/mv_web/live/member_live/show.ex
index 52b8250..5ac4fee 100644
--- a/lib/mv_web/live/member_live/show.ex
+++ b/lib/mv_web/live/member_live/show.ex
@@ -235,6 +235,19 @@ defmodule MvWeb.MemberLive.Show do
                       <%= for custom_field <- @custom_fields do %>
                         <% cfv = find_custom_field_value(@member.custom_field_values, custom_field.id) %>
                         <.data_field label={custom_field.name}>
+                          <:label_suffix :if={custom_field.join_description}>
+                            <.tooltip
+                              content={"#{gettext("Join form:")} #{custom_field.join_description}"}
+                              wrap_class="ml-1 inline-flex items-center"
+                            >
+                              <span data-testid="join-description-tooltip">
+                                <.icon
+                                  name="hero-information-circle"
+                                  class="size-3.5 text-base-content/50"
+                                />
+                              </span>
+                            </.tooltip>
+                          </:label_suffix>
                           {format_custom_field_value(cfv, custom_field.value_type)}
                         </.data_field>
                       <% end %>
@@ -605,11 +618,14 @@ defmodule MvWeb.MemberLive.Show do
   attr :value, :string, default: nil
   attr :class, :string, default: ""
   slot :inner_block
+  slot :label_suffix
 
   defp data_field(assigns) do
     ~H"""
     <dl class={@class}>
-      <dt class="text-sm font-medium text-base-content/70">{@label}</dt>
+      <dt class="text-sm font-medium text-base-content/70 flex items-center">
+        {@label}{render_slot(@label_suffix)}
+      </dt>
       <dd class="mt-1 text-base-content">
         <%= if @inner_block != [] do %>
           {render_slot(@inner_block)}
diff --git a/priv/gettext/de/LC_MESSAGES/default.po b/priv/gettext/de/LC_MESSAGES/default.po
index 81d91f7..4f895bb 100644
--- a/priv/gettext/de/LC_MESSAGES/default.po
+++ b/priv/gettext/de/LC_MESSAGES/default.po
@@ -3968,7 +3968,7 @@ msgstr "Zeitraum"
 msgid "To"
 msgstr "Bis"
 
-#~ #: lib/mv_web/live/group_live/show.ex
-#~ #, elixir-autogen, elixir-format
-#~ msgid "No members selected."
-#~ msgstr "Keine Mitglieder ausgewählt."
+#: lib/mv_web/live/member_live/show.ex
+#, elixir-autogen, elixir-format
+msgid "Join form:"
+msgstr "Beitrittsformular:"
diff --git a/priv/gettext/default.pot b/priv/gettext/default.pot
index 5e9abca..6bdbc40 100644
--- a/priv/gettext/default.pot
+++ b/priv/gettext/default.pot
@@ -3967,3 +3967,8 @@ msgstr ""
 #, elixir-autogen, elixir-format
 msgid "To"
 msgstr ""
+
+#: lib/mv_web/live/member_live/show.ex
+#, elixir-autogen, elixir-format
+msgid "Join form:"
+msgstr ""
diff --git a/priv/gettext/en/LC_MESSAGES/default.po b/priv/gettext/en/LC_MESSAGES/default.po
index 1ae6a49..82a52a6 100644
--- a/priv/gettext/en/LC_MESSAGES/default.po
+++ b/priv/gettext/en/LC_MESSAGES/default.po
@@ -3968,7 +3968,7 @@ msgstr ""
 msgid "To"
 msgstr ""
 
-#~ #: lib/mv_web/live/group_live/show.ex
-#~ #, elixir-autogen, elixir-format, fuzzy
-#~ msgid "No members selected."
-#~ msgstr ""
+#: lib/mv_web/live/member_live/show.ex
+#, elixir-autogen, elixir-format, fuzzy
+msgid "Join form:"
+msgstr ""
diff --git a/test/mv_web/member_live/show_test.exs b/test/mv_web/member_live/show_test.exs
index c451be9..2ec5a68 100644
--- a/test/mv_web/member_live/show_test.exs
+++ b/test/mv_web/member_live/show_test.exs
@@ -220,4 +220,59 @@ defmodule MvWeb.MemberLive.ShowTest do
       assert html =~ "private@example.com"
     end
   end
+
+  describe "custom field join_description tooltip" do
+    test "shows a tooltip on the custom field label when join_description is set", %{
+      conn: conn,
+      member: member,
+      actor: actor
+    } do
+      {:ok, custom_field} =
+        CustomField
+        |> Ash.Changeset.for_create(:create, %{
+          name: "DSGVO",
+          value_type: :boolean,
+          join_description: "Accept the privacy policy"
+        })
+        |> Ash.create(actor: actor)
+
+      conn = conn_with_oidc_user(conn)
+      {:ok, view, html} = live(conn, ~p"/members/#{member}")
+
+      assert has_element?(view, "[data-tip*='Accept the privacy policy']")
+      # Tooltip content conveys both the join-form context and the description text.
+      assert has_element?(view, "[data-tip*='Join form:']")
+      assert html =~ "Accept the privacy policy"
+      assert html =~ custom_field.name
+
+      # The info-icon wrapper must center the icon vertically with the label,
+      # matching the flex-items-center idiom used elsewhere (e.g. custom field edit),
+      # so the icon is flush with the label text and not offset downward.
+      assert has_element?(
+               view,
+               "[data-tip*='Accept the privacy policy'].inline-flex.items-center"
+             )
+    end
+
+    test "shows no tooltip on the custom field label when join_description is nil", %{
+      conn: conn,
+      member: member,
+      actor: actor
+    } do
+      {:ok, _custom_field} =
+        CustomField
+        |> Ash.Changeset.for_create(:create, %{
+          name: "Plain field",
+          value_type: :string
+        })
+        |> Ash.create(actor: actor)
+
+      conn = conn_with_oidc_user(conn)
+      {:ok, view, _html} = live(conn, ~p"/members/#{member}")
+
+      assert has_element?(view, "dt", "Plain field")
+      # The info-icon tooltip beside the label is only rendered when join_description is set.
+      refute has_element?(view, "[data-testid='join-description-tooltip']")
+    end
+  end
 end