diff --git a/src/haiku/rag/store/engine.py b/src/haiku/rag/store/engine.py
index 7e746bc7..612622ca 100644
--- a/src/haiku/rag/store/engine.py
+++ b/src/haiku/rag/store/engine.py
@@ -37,6 +37,11 @@ class Store:
         db = sqlite3.connect(self.db_path)
         db.enable_load_extension(True)
         sqlite_vec.load(db)
+
+        # Enable WAL mode for better concurrency (skip for in-memory databases)
+        if self.db_path != ":memory:":
+            db.execute("PRAGMA journal_mode=WAL")
+
         self._connection = db
         existing_tables = [
             row[0]