diff --git a/letta/services/message_manager.py b/letta/services/message_manager.py
index fb39b955..630324c0 100644
--- a/letta/services/message_manager.py
+++ b/letta/services/message_manager.py
@@ -303,17 +303,24 @@ class MessageManager:
             if group_id:
                 query = query.filter(MessageModel.group_id == group_id)
 
-            # If query_text is provided, filter messages using subquery + json_array_elements.
+            # If query_text is provided, filter messages by matching any "text" type content block
+            # whose text includes the query string (case-insensitive).
             if query_text:
-                content_element = func.json_array_elements(MessageModel.content).alias("content_element")
-                query = query.filter(
-                    exists(
-                        select(1)
-                        .select_from(content_element)
-                        .where(text("content_element->>'type' = 'text' AND content_element->>'text' ILIKE :query_text"))
-                        .params(query_text=f"%{query_text}%")
+                dialect_name = session.bind.dialect.name
+
+                if dialect_name == "postgresql":  # using subquery + json_array_elements.
+                    content_element = func.json_array_elements(MessageModel.content).alias("content_element")
+                    subquery_sql = text("content_element->>'type' = 'text' AND content_element->>'text' ILIKE :query_text")
+                    subquery = select(1).select_from(content_element).where(subquery_sql)
+
+                elif dialect_name == "sqlite":  # using `json_each` and JSON path expressions
+                    json_item = func.json_each(MessageModel.content).alias("json_item")
+                    subquery_sql = text(
+                        "json_extract(value, '$.type') = 'text' AND lower(json_extract(value, '$.text')) LIKE lower(:query_text)"
                     )
-                )
+                    subquery = select(1).select_from(json_item).where(subquery_sql)
+
+                query = query.filter(exists(subquery.params(query_text=f"%{query_text}%")))
 
             # If role(s) are provided, filter messages by those roles.
             if roles:
diff --git a/tests/test_managers.py b/tests/test_managers.py
index 3a9de069..a8a29309 100644
--- a/tests/test_managers.py
+++ b/tests/test_managers.py
@@ -1588,6 +1588,46 @@ def test_modify_letta_message(server: SyncServer, sarah_agent, default_user):
     # TODO: tool calls/responses
 
 
+def test_list_messages_with_query_text_filter(server: SyncServer, sarah_agent, default_user):
+    """
+    Ensure that list_messages_for_agent correctly filters messages by query_text.
+    """
+    test_contents = [
+        "This is a message about unicorns and rainbows.",
+        "Another message discussing dragons in the sky.",
+        "Plain message with no magical beasts.",
+        "Mentioning unicorns again for good measure.",
+        "Something unrelated entirely.",
+    ]
+
+    created_messages = []
+    for content in test_contents:
+        message = PydanticMessage(
+            agent_id=sarah_agent.id,
+            role=MessageRole.user,
+            content=[{"type": "text", "text": content}],
+        )
+        created = server.message_manager.create_message(pydantic_msg=message, actor=default_user)
+        created_messages.append(created)
+
+    # Query messages that include "unicorns"
+    unicorn_messages = server.message_manager.list_messages_for_agent(agent_id=sarah_agent.id, actor=default_user, query_text="unicorns")
+    assert len(unicorn_messages) == 2
+    for msg in unicorn_messages:
+        assert any(chunk.type == "text" and "unicorns" in chunk.text.lower() for chunk in msg.content or [])
+
+    # Query messages that include "dragons"
+    dragon_messages = server.message_manager.list_messages_for_agent(agent_id=sarah_agent.id, actor=default_user, query_text="dragons")
+    assert len(dragon_messages) == 1
+    assert any(chunk.type == "text" and "dragons" in chunk.text.lower() for chunk in dragon_messages[0].content or [])
+
+    # Query with a word that shouldn't match any message
+    no_match_messages = server.message_manager.list_messages_for_agent(
+        agent_id=sarah_agent.id, actor=default_user, query_text="nonexistentcreature"
+    )
+    assert len(no_match_messages) == 0
+
+
 # ======================================================================================================================
 # AgentManager Tests - Blocks Relationship
 # ======================================================================================================================