diff --git a/moto/cognitoidp/responses.py b/moto/cognitoidp/responses.py
index 80247b076..fa3b7b0b5 100644
--- a/moto/cognitoidp/responses.py
+++ b/moto/cognitoidp/responses.py
@@ -279,9 +279,18 @@ class CognitoIdpResponse(BaseResponse):
         user_pool_id = self._get_param("UserPoolId")
         limit = self._get_param("Limit")
         token = self._get_param("PaginationToken")
+        filt = self._get_param("Filter")
         users, token = cognitoidp_backends[self.region].list_users(
             user_pool_id, limit=limit, pagination_token=token
         )
+        if filt:
+            name, value = filt.replace('"', "").split("=")
+            users = [
+                user
+                for user in users
+                for attribute in user.attributes
+                if attribute["Name"] == name and attribute["Value"] == value
+            ]
         response = {"Users": [user.to_json(extended=True) for user in users]}
         if token:
             response["PaginationToken"] = str(token)
diff --git a/tests/test_cognitoidp/test_cognitoidp.py b/tests/test_cognitoidp/test_cognitoidp.py
index 6a13683f0..2f7ed11e5 100644
--- a/tests/test_cognitoidp/test_cognitoidp.py
+++ b/tests/test_cognitoidp/test_cognitoidp.py
@@ -958,6 +958,18 @@ def test_list_users():
     result["Users"].should.have.length_of(1)
     result["Users"][0]["Username"].should.equal(username)
 
+    username_bis = str(uuid.uuid4())
+    conn.admin_create_user(
+        UserPoolId=user_pool_id,
+        Username=username_bis,
+        UserAttributes=[{"Name": "phone_number", "Value": "+33666666666"}],
+    )
+    result = conn.list_users(
+        UserPoolId=user_pool_id, Filter='phone_number="+33666666666'
+    )
+    result["Users"].should.have.length_of(1)
+    result["Users"][0]["Username"].should.equal(username_bis)
+
 
 @mock_cognitoidp
 def test_list_users_returns_limit_items():