diff --git a/src/qt/rpcconsole.cpp b/src/qt/rpcconsole.cpp
--- a/src/qt/rpcconsole.cpp
+++ b/src/qt/rpcconsole.cpp
@@ -539,6 +539,7 @@
 
     // Install event filter for up and down arrow
     ui->lineEdit->installEventFilter(this);
+    ui->lineEdit->setMaxLength(16 * 1024 * 1024);
     ui->messagesWidget->installEventFilter(this);
 
     connect(ui->clearButton, &QPushButton::clicked, this, &RPCConsole::clear);