diff --git a/src/wallet/wallet.h b/src/wallet/wallet.h
index 3731d80675..cdbf09914f 100644
--- a/src/wallet/wallet.h
+++ b/src/wallet/wallet.h
@@ -83,6 +83,8 @@ class CWalletTx;
 struct FeeCalculation;
 enum class FeeEstimateMode;
 
+extern CCriticalSection cs_main;
+
 /** (client) version numbers for particular wallet features */
 enum WalletFeature
 {