diff --git a/src/wallet/rpc/encrypt.cpp b/src/wallet/rpc/encrypt.cpp
index 0226d15698bab8..3e3c3b87c374bb 100644
--- a/src/wallet/rpc/encrypt.cpp
+++ b/src/wallet/rpc/encrypt.cpp
@@ -18,7 +18,7 @@ RPCHelpMan walletpassphrase()
             "time that overrides the old one.\n",
                 {
                     {"passphrase", RPCArg::Type::STR, RPCArg::Optional::NO, "The wallet passphrase"},
-                    {"timeout", RPCArg::Type::NUM, RPCArg::Optional::NO, "The time to keep the decryption key in seconds; capped at 100000000 (~3 years)."},
+                    {"timeout", RPCArg::Type::NUM, RPCArg::Optional::OMITTED, "The time to keep the decryption key in seconds; capped at 100000000 (~3 years), will use cap if left empty"},
                 },
                 RPCResult{RPCResult::Type::NONE, "", ""},
                 RPCExamples{
@@ -35,7 +35,8 @@ RPCHelpMan walletpassphrase()
     if (!wallet) return UniValue::VNULL;
     CWallet* const pwallet = wallet.get();
 
-    int64_t nSleepTime;
+    constexpr int64_t MAX_SLEEP_TIME = 100000000; // larger values trigger a macos/libevent bug?
+    int64_t nSleepTime = MAX_SLEEP_TIME;
     int64_t relock_time;
     // Prevent concurrent calls to walletpassphrase with the same wallet.
     LOCK(pwallet->m_unlock_mutex);
@@ -51,16 +52,17 @@ RPCHelpMan walletpassphrase()
         strWalletPass.reserve(100);
         strWalletPass = std::string_view{request.params[0].get_str()};
 
-        // Get the timeout
-        nSleepTime = request.params[1].getInt<int64_t>();
-        // Timeout cannot be negative, otherwise it will relock immediately
-        if (nSleepTime < 0) {
-            throw JSONRPCError(RPC_INVALID_PARAMETER, "Timeout cannot be negative.");
-        }
-        // Clamp timeout
-        constexpr int64_t MAX_SLEEP_TIME = 100000000; // larger values trigger a macos/libevent bug?
-        if (nSleepTime > MAX_SLEEP_TIME) {
-            nSleepTime = MAX_SLEEP_TIME;
+        if(!request.params[1].isNull()){
+            // Get the timeout
+            nSleepTime = request.params[1].getInt<int64_t>();
+            // Timeout cannot be negative, otherwise it will relock immediately
+            if (nSleepTime < 0) {
+                throw JSONRPCError(RPC_INVALID_PARAMETER, "Timeout cannot be negative.");
+            }
+            // Clamp timeout
+            if (nSleepTime > MAX_SLEEP_TIME) {
+                nSleepTime = MAX_SLEEP_TIME;
+            }
         }
 
         if (strWalletPass.empty()) {