diff --git a/src/platform/OpenThread/GenericThreadStackManagerImpl_OpenThread.h b/src/platform/OpenThread/GenericThreadStackManagerImpl_OpenThread.h
index 71ca8d9ff65540..f5e999dd458941 100644
--- a/src/platform/OpenThread/GenericThreadStackManagerImpl_OpenThread.h
+++ b/src/platform/OpenThread/GenericThreadStackManagerImpl_OpenThread.h
@@ -120,7 +120,7 @@ class GenericThreadStackManagerImpl_OpenThread
     struct SrpClient
     {
         static constexpr uint8_t kMaxServicesNumber   = CHIP_DEVICE_CONFIG_THREAD_SRP_MAX_SERVICES;
-        static constexpr uint8_t kMaxInstanceNameSize = chip::Mdns::kMdnsNameMaxSize;
+        static constexpr uint8_t kMaxInstanceNameSize = chip::Mdns::kMdnsNameMaxSize + 1;
         static constexpr uint8_t kMaxNameSize         = chip::Mdns::kMdnsTypeMaxSize + chip::Mdns::kMdnsProtocolTextMaxSize + 1;
         static constexpr uint8_t kMaxHostNameSize     = 32;
         // Thread only supports operational discovery