diff --git a/plugins/ledger/qt.py b/plugins/ledger/qt.py
index aa83df24..ec46c116 100644
--- a/plugins/ledger/qt.py
+++ b/plugins/ledger/qt.py
@@ -1,5 +1,6 @@
 from PyQt4.Qt import QApplication, QMessageBox, QDialog, QInputDialog, QLineEdit, QVBoxLayout, QLabel, QThread, SIGNAL
 import PyQt4.QtCore as QtCore
+import threading
 
 from electrum_gui.qt.password_dialog import make_password_dialog, run_password_dialog
 from electrum.plugins import BasePlugin, hook