diff --git a/changelogs/fragments/11502-keycloak-config-mapper.yaml b/changelogs/fragments/11502-keycloak-config-mapper.yaml
new file mode 100644
index 0000000000..b7c1c1d186
--- /dev/null
+++ b/changelogs/fragments/11502-keycloak-config-mapper.yaml
@@ -0,0 +1,2 @@
+bugfixes:
+  - "keycloak_user_federation - mapper config item can be an array (https://github.com/ansible-collections/community.general/issues/11502, https://github.com/ansible-collections/community.general/pull/11515)."
diff --git a/plugins/modules/keycloak_user_federation.py b/plugins/modules/keycloak_user_federation.py
index c448d0247f..479d4ec015 100644
--- a/plugins/modules/keycloak_user_federation.py
+++ b/plugins/modules/keycloak_user_federation.py
@@ -744,15 +744,30 @@ def normalize_kc_comp(comp):
 
 
 def sanitize(comp):
+    def sanitize_value(v):
+        """Convert list values: single-element lists to strings, multi-element lists sorted alphabetically, others as-is."""
+        if isinstance(v, list):
+            if len(v) == 0:
+                return None
+            elif len(v) == 1:
+                return v[0]
+            else:
+                return sorted(v)
+        else:
+            return v
+
     compcopy = deepcopy(comp)
     if "config" in compcopy:
-        compcopy["config"] = {k: v[0] for k, v in compcopy["config"].items()}
+        compcopy["config"] = {k: sanitize_value(v) for k, v in compcopy["config"].items()}
+        # Remove None values (empty lists converted)
+        compcopy["config"] = {k: v for k, v in compcopy["config"].items() if v is not None}
         if "bindCredential" in compcopy["config"]:
             compcopy["config"]["bindCredential"] = "**********"
     if "mappers" in compcopy:
         for mapper in compcopy["mappers"]:
             if "config" in mapper:
-                mapper["config"] = {k: v[0] for k, v in mapper["config"].items()}
+                mapper["config"] = {k: sanitize_value(v) for k, v in mapper["config"].items()}
+                mapper["config"] = {k: v for k, v in mapper["config"].items() if v is not None}
     return compcopy
 
 
@@ -886,11 +901,15 @@ def main():
     if mappers is not None:
         for mapper in mappers:
             if mapper.get("config") is not None:
-                mapper["config"] = {
-                    k: [str(v).lower() if not isinstance(v, str) else v]
-                    for k, v in mapper["config"].items()
-                    if mapper["config"][k] is not None
-                }
+                new_config = {}
+                for k, v in mapper["config"].items():
+                    if v is None:
+                        continue
+                    if isinstance(v, list):
+                        new_config[k] = [str(item).lower() if not isinstance(item, str) else item for item in v]
+                    else:
+                        new_config[k] = [str(v).lower() if not isinstance(v, str) else v]
+                mapper["config"] = new_config
 
     # Filter and map the parameters names that apply
     comp_params = [