diff --git a/docs/storage-backends.md b/docs/storage-backends.md
index bb05e115..dc211ef0 100644
--- a/docs/storage-backends.md
+++ b/docs/storage-backends.md
@@ -35,7 +35,7 @@ This page is intentionally conservative: it distinguishes between an adapter exi
 | FalkorDB | LPG | Yes | Yes | Partial | Partial | Redis-based; provenance depends on node/edge properties, and multi-graph isolation depends on the selected graph name. |
 | Amazon Neptune | LPG | Yes | Yes | Partial | Partial | Use the property-graph endpoint; AWS auth, VPC, and endpoint configuration can affect local tests. Provenance depends on node/edge properties. |
 | Apache AGE | LPG | Yes | Yes | Partial | Partial | Runs through PostgreSQL/AGE; Cypher compatibility and property handling can differ from standalone LPG engines. |
-| RDF4J | RDF | Yes | Partial | Partial | Partial | Context separation relies on named graphs; triple-level provenance may require reification or graph-level metadata. `RDF4JStore(repository_id=...)` currently has no effect — the constructor always connects to the `"default"` repository regardless of the value passed; track a fix separately. |
+| RDF4J | RDF | Yes | Partial | Partial | Partial | Context separation relies on named graphs; triple-level provenance may require reification or graph-level metadata. |
 | Apache Jena | RDF | Yes | Partial | Partial | Partial | Named graphs are needed for context separation; backend configuration and transaction behavior matter. |
 | Blazegraph | RDF | Yes | Partial | Partial | Partial | Use quads/named graphs for context; IRI stability and graph naming matter for provenance. |
 | Anzo | RDF | Yes | Partial | Partial | Partial | Anzo deployments are environment-specific; validate `dataset_uri`/graphmart naming, named-graph support, and provenance mapping. |
@@ -107,7 +107,7 @@ from semantica.triplet_store import RDF4JStore
 
 store = RDF4JStore(
     endpoint='http://localhost:8080/rdf4j-server',
-    repository_id='semantica'  # currently has no effect; connects to "default" (see Known limitations)
+    repository_id='semantica'
 )
 ```
 
diff --git a/semantica/triplet_store/rdf4j_store.py b/semantica/triplet_store/rdf4j_store.py
index 8dad6997..c03b64a8 100644
--- a/semantica/triplet_store/rdf4j_store.py
+++ b/semantica/triplet_store/rdf4j_store.py
@@ -67,7 +67,7 @@ class RDF4JStore:
             self.progress_tracker.enabled = True
 
         self.endpoint = endpoint.rstrip("/")
-        self.repository_id = config.get("repository_id", "default")
+        self.repository_id = repository_id or config.get("repository_id", "default")
         self.username = config.get("username")
         self.password = config.get("password")
         self.timeout = config.get("timeout", 30)
diff --git a/tests/triplet_store/test_rdf4j_store.py b/tests/triplet_store/test_rdf4j_store.py
index 4ef4f16b..3f630b93 100644
--- a/tests/triplet_store/test_rdf4j_store.py
+++ b/tests/triplet_store/test_rdf4j_store.py
@@ -22,6 +22,27 @@ def _make_connected_store():
 CONSTRUCT_QUERY = "CONSTRUCT { ?s ?p ?o } WHERE { ?s ?p ?o }"
 
 
+class TestRDF4JStoreInitialization(unittest.TestCase):
+    def test_explicit_repository_id_selects_repository(self):
+        response = MagicMock(status_code=200)
+
+        with patch(
+            "semantica.triplet_store.rdf4j_store.requests.get",
+            return_value=response,
+        ) as mock_get:
+            store = RDF4JStore(
+                endpoint="http://localhost:8080/rdf4j-server/",
+                repository_id="semantica",
+            )
+
+        self.assertEqual(store.repository_id, "semantica")
+        mock_get.assert_called_once_with(
+            "http://localhost:8080/rdf4j-server/repositories/semantica",
+            timeout=30,
+            auth=None,
+        )
+
+
 class TestRDF4JStoreIsConstructQuery(unittest.TestCase):
     def test_detects_uppercase(self):
         self.assertTrue(_make_connected_store()._is_construct_query(