diff --git a/src/core/hle/service/gsp/gsp_gpu.cpp b/src/core/hle/service/gsp/gsp_gpu.cpp
index 5a41f5ca0..3b32b47d0 100644
--- a/src/core/hle/service/gsp/gsp_gpu.cpp
+++ b/src/core/hle/service/gsp/gsp_gpu.cpp
@@ -78,7 +78,7 @@ static PAddr VirtualToPhysicalAddress(VAddr addr) {
     return addr | 0x80000000;
 }
 
-u32 GSP_GPU::GetUnusedThreadId() {
+u32 GSP_GPU::GetUnusedThreadId() const {
     for (u32 id = 0; id < MaxGSPThreads; ++id) {
         if (!used_thread_ids[id])
             return id;
diff --git a/src/core/hle/service/gsp/gsp_gpu.h b/src/core/hle/service/gsp/gsp_gpu.h
index c8914ef72..4d961634a 100644
--- a/src/core/hle/service/gsp/gsp_gpu.h
+++ b/src/core/hle/service/gsp/gsp_gpu.h
@@ -424,7 +424,7 @@ private:
     /// Returns the session data for the specified registered thread id, or nullptr if not found.
     SessionData* FindRegisteredThreadData(u32 thread_id);
 
-    u32 GetUnusedThreadId();
+    u32 GetUnusedThreadId() const;
 
     std::unique_ptr<Kernel::SessionRequestHandler::SessionDataBase> MakeSessionData() override;