diff --git a/include/modules/sway/ipc/client.hpp b/include/modules/sway/ipc/client.hpp
index 6ab3c6cc..ddd4c5ac 100644
--- a/include/modules/sway/ipc/client.hpp
+++ b/include/modules/sway/ipc/client.hpp
@@ -44,6 +44,7 @@ class Ipc {
   int              fd_event_;
   std::mutex       mutex_;
   std::mutex       mutex_event_;
+  std::mutex       mutex_parser_;
   util::JsonParser parser_;
 };
 
diff --git a/src/modules/sway/ipc/client.cpp b/src/modules/sway/ipc/client.cpp
index 7c5db7c5..dc121fa9 100644
--- a/src/modules/sway/ipc/client.cpp
+++ b/src/modules/sway/ipc/client.cpp
@@ -104,6 +104,7 @@ struct Ipc::ipc_response Ipc::recv(int fd) {
     }
     total += res;
   }
+  std::lock_guard<std::mutex> lock(mutex_parser_);
   auto parsed = parser_.parse(&payload.front());
   return {data32[0], data32[1], parsed};
 }