diff --git a/pinecone/grpc/base.py b/pinecone/grpc/base.py
index cc4ca2c6..8964e72d 100644
--- a/pinecone/grpc/base.py
+++ b/pinecone/grpc/base.py
@@ -10,6 +10,7 @@
 from pinecone import Config
 from .config import GRPCClientConfig
 from .grpc_runner import GrpcRunner
+from concurrent.futures import ThreadPoolExecutor
 
 from pinecone_plugin_interface import load_and_install as install_plugins
 
@@ -29,10 +30,12 @@ def __init__(
         config: Config,
         channel: Optional[Channel] = None,
         grpc_config: Optional[GRPCClientConfig] = None,
+        pool_threads: Optional[int] = None,
         _endpoint_override: Optional[str] = None,
     ):
         self.config = config
         self.grpc_client_config = grpc_config or GRPCClientConfig()
+        self.pool_threads = pool_threads
 
         self._endpoint_override = _endpoint_override
 
@@ -58,6 +61,13 @@ def stub_openapi_client_builder(*args, **kwargs):
         except Exception as e:
             _logger.error(f"Error loading plugins in GRPCIndex: {e}")
 
+    @property
+    def threadpool_executor(self):
+        if self._pool is None:
+            pt = self.pool_threads or 10
+            self._pool = ThreadPoolExecutor(max_workers=pt)
+        return self._pool
+
     @property
     @abstractmethod
     def stub_class(self):
diff --git a/pinecone/grpc/index_grpc.py b/pinecone/grpc/index_grpc.py
index eba611b7..6791ae68 100644
--- a/pinecone/grpc/index_grpc.py
+++ b/pinecone/grpc/index_grpc.py
@@ -1,9 +1,11 @@
 import logging
-from typing import Optional, Dict, Union, List, Tuple, Any, TypedDict, cast
+from typing import Optional, Dict, Union, List, Tuple, Any, TypedDict, Iterable, cast
 
 from google.protobuf import json_format
 
 from tqdm.autonotebook import tqdm
+from concurrent.futures import as_completed, Future
+
 
 from .utils import (
     dict_to_proto_struct,
@@ -35,6 +37,7 @@
     SparseValues as GRPCSparseValues,
 )
 from pinecone import Vector as NonGRPCVector
+from pinecone.data.query_results_aggregator import QueryNamespacesResults, QueryResultsAggregator
 from pinecone.core.grpc.protos.vector_service_pb2_grpc import VectorServiceStub
 from .base import GRPCIndexBase
 from .future import PineconeGrpcFuture
@@ -402,6 +405,49 @@ def query(
             json_response = json_format.MessageToDict(response)
             return parse_query_response(json_response, _check_type=False)
 
+    def query_namespaces(
+        self,
+        vector: List[float],
+        namespaces: List[str],
+        top_k: Optional[int] = None,
+        filter: Optional[Dict[str, Union[str, float, int, bool, List, dict]]] = None,
+        include_values: Optional[bool] = None,
+        include_metadata: Optional[bool] = None,
+        sparse_vector: Optional[Union[GRPCSparseValues, SparseVectorTypedDict]] = None,
+        **kwargs,
+    ) -> QueryNamespacesResults:
+        if namespaces is None or len(namespaces) == 0:
+            raise ValueError("At least one namespace must be specified")
+        if len(vector) == 0:
+            raise ValueError("Query vector must not be empty")
+
+        overall_topk = top_k if top_k is not None else 10
+        aggregator = QueryResultsAggregator(top_k=overall_topk)
+
+        target_namespaces = set(namespaces)  # dedup namespaces
+        futures = [
+            self.threadpool_executor.submit(
+                self.query,
+                vector=vector,
+                namespace=ns,
+                top_k=overall_topk,
+                filter=filter,
+                include_values=include_values,
+                include_metadata=include_metadata,
+                sparse_vector=sparse_vector,
+                async_req=False,
+                **kwargs,
+            )
+            for ns in target_namespaces
+        ]
+
+        only_futures = cast(Iterable[Future], futures)
+        for response in as_completed(only_futures):
+            aggregator.add_results(response.result())
+
+        final_results = aggregator.get_results()
+        return final_results
+
     def update(
         self,
         id: str,
diff --git a/pinecone/grpc/pinecone.py b/pinecone/grpc/pinecone.py
index af6a8baa..c78481ff 100644
--- a/pinecone/grpc/pinecone.py
+++ b/pinecone/grpc/pinecone.py
@@ -124,6 +124,8 @@ def Index(self, name: str = "", host: str = "", **kwargs):
         # Use host if it is provided, otherwise get host from describe_index
         index_host = host or self.index_host_store.get_host(self.index_api, self.config, name)
 
+        pt = kwargs.pop("pool_threads", None) or self.pool_threads
+
         config = ConfigBuilder.build(
             api_key=self.config.api_key,
             host=index_host,
@@ -131,4 +133,4 @@ def Index(self, name: str = "", host: str = "", **kwargs):
             proxy_url=self.config.proxy_url,
             ssl_ca_certs=self.config.ssl_ca_certs,
         )
-        return GRPCIndex(index_name=name, config=config, **kwargs)
+        return GRPCIndex(index_name=name, config=config, pool_threads=pt, **kwargs)
diff --git a/tests/integration/data/test_query_namespaces.py b/tests/integration/data/test_query_namespaces.py
index e52c58b0..414cea69 100644
--- a/tests/integration/data/test_query_namespaces.py
+++ b/tests/integration/data/test_query_namespaces.py
@@ -1,5 +1,4 @@
 import pytest
-import os
 from ..helpers import random_string, poll_stats_for_namespace
 from pinecone.data.query_results_aggregator import (
     QueryResultsAggregatorInvalidTopKError,
@@ -9,9 +8,6 @@
 from pinecone import Vector
 
 
-@pytest.mark.skipif(
-    os.getenv("USE_GRPC") == "true", reason="query_namespaces currently only available via rest"
-)
 class TestQueryNamespacesRest:
     def test_query_namespaces(self, idx):
         ns_prefix = random_string(5)