diff --git a/push/include/prometheus/gateway.h b/push/include/prometheus/gateway.h
index 665a858b..c139320d 100644
--- a/push/include/prometheus/gateway.h
+++ b/push/include/prometheus/gateway.h
@@ -3,6 +3,7 @@
 #include <future>
 #include <map>
 #include <memory>
+#include <mutex>
 #include <string>
 #include <utility>
 #include <vector>
@@ -57,6 +58,7 @@ class PROMETHEUS_CPP_PUSH_EXPORT Gateway {
   std::string jobUri_;
   std::string labels_;
   std::unique_ptr<detail::CurlWrapper> curlWrapper_;
+  std::mutex mutex_;
 
   using CollectableEntry = std::pair<std::weak_ptr<Collectable>, std::string>;
   std::vector<CollectableEntry> collectables_;
diff --git a/push/src/gateway.cc b/push/src/gateway.cc
index f1b8ef73..e7acf13a 100644
--- a/push/src/gateway.cc
+++ b/push/src/gateway.cc
@@ -55,6 +55,7 @@ void Gateway::RegisterCollectable(const std::weak_ptr<Collectable>& collectable,
     }
   }
 
+  std::lock_guard<std::mutex> lock{mutex_};
   CleanupStalePointers(collectables_);
   collectables_.push_back(std::make_pair(collectable, ss.str()));
 }
@@ -73,6 +74,7 @@ int Gateway::PushAdd() { return push(detail::HttpMethod::Put); }
 int Gateway::push(detail::HttpMethod method) {
   const auto serializer = TextSerializer{};
 
+  std::lock_guard<std::mutex> lock{mutex_};
   for (auto& wcollectable : collectables_) {
     auto collectable = wcollectable.first.lock();
     if (!collectable) {
@@ -104,6 +106,7 @@ std::future<int> Gateway::async_push(detail::HttpMethod method) {
   const auto serializer = TextSerializer{};
   std::vector<std::future<int>> futures;
 
+  std::lock_guard<std::mutex> lock{mutex_};
   for (auto& wcollectable : collectables_) {
     auto collectable = wcollectable.first.lock();
     if (!collectable) {