diff --git a/lib/internal/readline/interface.js b/lib/internal/readline/interface.js
index 4fd69d43c48561..46674883381392 100644
--- a/lib/internal/readline/interface.js
+++ b/lib/internal/readline/interface.js
@@ -658,6 +658,12 @@ class Interface extends InterfaceConstructor {
 
   [kInsertString](c) {
     this[kBeforeEdit](this.line, this.cursor);
+    if (!this.isCompletionEnabled) {
+      this.line += c;
+      this.cursor += c.length;
+      this[kWriteToOutput](c);
+      return;
+    }
     if (this.cursor < this.line.length) {
       const beg = StringPrototypeSlice(this.line, 0, this.cursor);
       const end = StringPrototypeSlice(
diff --git a/test/parallel/test-repl-paste-big-data.js b/test/parallel/test-repl-paste-big-data.js
new file mode 100644
index 00000000000000..fd247b4b063192
--- /dev/null
+++ b/test/parallel/test-repl-paste-big-data.js
@@ -0,0 +1,36 @@
+'use strict';
+
+const common = require('../common');
+const repl = require('repl');
+const stream = require('stream');
+const assert = require('assert');
+
+// Pasting big input should not cause the process to have a huge CPU usage.
+
+const cpuUsage = process.cpuUsage();
+
+const r = initRepl();
+r.input.emit('data', 'a'.repeat(2e4) + '\n');
+r.input.emit('data', '.exit\n');
+
+r.once('exit', common.mustCall(() => {
+  const diff = process.cpuUsage(cpuUsage);
+  assert.ok(diff.user < 1e6);
+}));
+
+function initRepl() {
+  const input = new stream();
+  input.write = input.pause = input.resume = () => {};
+  input.readable = true;
+
+  const output = new stream();
+  output.write = () => {};
+  output.writable = true;
+
+  return repl.start({
+    input,
+    output,
+    terminal: true,
+    prompt: ''
+  });
+}