diff --git a/osbenchmark/workload/params.py b/osbenchmark/workload/params.py
index 83aa7f1d4..a2bc74156 100644
--- a/osbenchmark/workload/params.py
+++ b/osbenchmark/workload/params.py
@@ -1097,6 +1097,7 @@ class VectorSearchPartitionParamSource(VectorDataSetPartitionParamSource):
     PARAMS_NAME_REQUEST_PARAMS = "request-params"
     PARAMS_NAME_SOURCE = "_source"
     PARAMS_NAME_ALLOW_PARTIAL_RESULTS = "allow_partial_search_results"
+    PARAMS_NAME_EF_SEARCH = "hnsw_ef_search"
 
     def __init__(self, workloads, params, query_params, **kwargs):
         super().__init__(workloads, params, Context.QUERY, **kwargs)
@@ -1121,8 +1122,7 @@ def __init__(self, workloads, params, query_params, **kwargs):
 
         self.filter_type = self.query_params.get(self.PARAMS_NAME_FILTER_TYPE)
         self.filter_body = self.query_params.get(self.PARAMS_NAME_FILTER_BODY)
-
-
+        self.ef_search = self.query_params.get(self.PARAMS_NAME_EF_SEARCH)
         if self.PARAMS_NAME_FILTER in params:
             self.query_params.update({
                 self.PARAMS_NAME_FILTER:  params.get(self.PARAMS_NAME_FILTER)
@@ -1226,6 +1226,10 @@ def _build_vector_search_query_body(self, vector, efficient_filter=None, filter_
             "vector": vector,
             "k": self.k,
         }
+        if self.ef_search is not None:
+            query["method_parameters"] = {
+                "ef_search": self.ef_search
+            }
         if efficient_filter:
             query.update({
                 "filter": efficient_filter,