diff --git a/.travis.yml b/.travis.yml
index 72b07382..f0ea98c0 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,5 +1,8 @@
 # vim: set ts=2 et:
 
+# run xvfb with 32-bit color
+# xvfb-run -s '-screen 0 1600x1200x24+32' command_goes_here
+
 matrix:
   include:
 
@@ -15,13 +18,59 @@ matrix:
         apt:
           packages:
             - cmake
+            - python-qt4
             - pyqt4-dev-tools
             - xvfb
       before_install:
         - sudo pip install lxml
-        - make qt4
+        - make qt4py2
         - ( xvfb-run python2.7 labelImg.py ) & sleep 10 ; kill $!
 
+    # Python 2 + QT5
+    # disabled; can't get it to work
+    #- os: linux
+    #  dist: trusty
+    #  sudo: required
+    #  language: generic
+    #  python: "2.7"
+    #  env:
+    #    - QT=5
+    #  addons:
+    #    apt:
+    #      packages:
+    #        - cmake
+    #        - pyqt5-dev-tools
+    #        - xvfb
+    #  before_install:
+    #    - sudo apt-get update
+    #    - sudo apt-get install -y python-pip
+    #    - sudo pip install lxml
+    #    - pyrcc5 --help || true  # does QT5 support python2 out of the box?
+    #    - make qt5py3
+    #    - ( xvfb-run python2.7 labelImg.py ) & sleep 10 ; kill $!
+
+    # Python 3 + QT4
+    - os: linux
+      dist: trusty
+      sudo: required
+      language: generic
+      python: "3.4"
+      env:
+        - QT=4
+      addons:
+        apt:
+          packages:
+            - cmake
+            - python3-pyqt4
+            - pyqt4-dev-tools
+            - xvfb
+      before_install:
+        - sudo apt-get update
+        - sudo apt-get install -y python3-pip
+        - sudo pip3 install lxml
+        - make qt4py3
+        - ( xvfb-run python3 labelImg.py ) & sleep 10 ; kill $!
+
     # Python 3 + QT5
     - os: linux
       dist: trusty
@@ -34,13 +83,13 @@ matrix:
         apt:
           packages:
             - cmake
+            - pyqt5-dev-tools
             - xvfb
       before_install:
         - sudo apt-get update
-        - sudo apt-get install -y pyqt5-dev-tools
         - sudo apt-get install -y python3-pip
         - sudo pip3 install lxml
-        - make qt5
+        - make qt5py3
         - ( xvfb-run python3 labelImg.py ) & sleep 10 ; kill $!
 
     # OS X Python 3 + QT5
@@ -61,7 +110,7 @@ matrix:
         - sudo -H easy_install-3.6 lxml || true
         - python3 -c 'import sys; print(sys.path)'
         - python3 -c 'import lxml'
-        - make qt5
+        - make qt5py3
         - python3 -c 'help("modules")'
         - ( python3 labelImg.py ) & sleep 10 ; kill $!
 
diff --git a/Makefile b/Makefile
index 28aa5a63..54c88897 100644
--- a/Makefile
+++ b/Makefile
@@ -1,6 +1,16 @@
 
-all: resources.py
+all: qt4
 
-%.py: %.qrc
-	pyrcc4 -o $@ $<
+qt4: qt4py2
+
+qt5: qt4py3
+
+qt4py2:
+	pyrcc4 -py2 -o resources.py resources.qrc
+
+qt4py3:
+	pyrcc4 -py3 -o resources.py resources.qrc
+
+qt5py3:
+	pyrcc5 -o resources.py resources.qrc
 
diff --git a/labelImg.py b/labelImg.py
index 35d4bb34..a79e1c39 100755
--- a/labelImg.py
+++ b/labelImg.py
@@ -10,8 +10,19 @@ import subprocess
 from functools import partial
 from collections import defaultdict
 
-from PyQt4.QtGui import *
-from PyQt4.QtCore import *
+try:
+    from PyQt5.QtGui import *
+    from PyQt5.QtCore import *
+    from PyQt5.QtWidgets import *
+except ImportError:
+    # needed for py3+qt4
+    # ref: http://pyqt.sourceforge.net/Docs/PyQt4/incompatible_apis.html
+    # ref: http://stackoverflow.com/questions/21217399/pyqt4-qtcore-qvariant-object-instead-of-a-string
+    if sys.version_info.major >= 3:
+        import sip
+        sip.setapi('QVariant', 2)
+    from PyQt4.QtGui import *
+    from PyQt4.QtCore import *
 
 import resources
 
@@ -31,13 +42,22 @@ __appname__ = 'labelImg'
 
 
 def u(x):
-    '''unicode helper'''
+    '''py2/py3 unicode helper'''
     try:
         return x.decode('utf8')  # py2
     except AttributeError:
         return x  # py3
 
 
+def have_qstring():
+    '''p3/qt5 get rid of QString wrapper as py3 has native unicode str type'''
+    return not (sys.version_info.major >= 3 or QT_VERSION_STR.startswith('5.'))
+
+
+def util_qt_strlistclass():
+    return QStringList if have_qstring() else list
+
+
 class WindowMixin(object):
     def menu(self, title, actions=None):
         menu = self.menuBar().addMenu(title)
@@ -56,6 +76,14 @@ class WindowMixin(object):
         return toolbar
 
 
+# PyQt5: TypeError: unhashable type: 'QListWidgetItem'
+class HashableQListWidgetItem(QListWidgetItem):
+    def __init__(self, *args):
+        super(HashableQListWidgetItem, self).__init__(*args)
+    def __hash__(self):
+        return hash(id(self))
+
+
 class MainWindow(QMainWindow, WindowMixin):
     FIT_WINDOW, FIT_WIDTH, MANUAL_ZOOM = list(range(3))
 
@@ -332,19 +360,40 @@ class MainWindow(QMainWindow, WindowMixin):
 
         # XXX: Could be completely declarative.
         # Restore application settings.
-        types = {
-            'filename': QString,
-            'recentFiles': QStringList,
-            'window/size': QSize,
-            'window/position': QPoint,
-            'window/geometry': QByteArray,
-            # Docks and toolbars:
-            'window/state': QByteArray,
-            'savedir': QString,
-            'lastOpenDir': QString,
-        }
+
+        if have_qstring():
+            types = {
+                'filename': QString,
+                'recentFiles': QStringList,
+                'window/size': QSize,
+                'window/position': QPoint,
+                'window/geometry': QByteArray,
+                'line/color': QColor,
+                'fill/color': QColor,
+                'advanced': bool,
+                # Docks and toolbars:
+                'window/state': QByteArray,
+                'savedir': QString,
+                'lastOpenDir': QString,
+            }
+        else:
+            types = {
+                'filename': str,
+                'recentFiles': list,
+                'window/size': QSize,
+                'window/position': QPoint,
+                'window/geometry': QByteArray,
+                'line/color': QColor,
+                'fill/color': QColor,
+                'advanced': bool,
+                # Docks and toolbars:
+                'window/state': QByteArray,
+                'savedir': str,
+                'lastOpenDir': str,
+            }
+
         self.settings = settings = Settings(types)
-        self.recentFiles = list(settings['recentFiles'])
+        self.recentFiles = list(settings.get('recentFiles', []))
         size = settings.get('window/size', QSize(600, 500))
         position = settings.get('window/position', QPoint(0, 0))
         self.resize(size)
@@ -358,13 +407,18 @@ class MainWindow(QMainWindow, WindowMixin):
 
         # or simply:
         #self.restoreGeometry(settings['window/geometry']
-        self.restoreState(settings['window/state'])
+        self.restoreState(settings.get('window/state', QByteArray()))
         self.lineColor = QColor(settings.get('line/color', Shape.line_color))
         self.fillColor = QColor(settings.get('fill/color', Shape.fill_color))
         Shape.line_color = self.lineColor
         Shape.fill_color = self.fillColor
 
-        if settings.get('advanced', QVariant()).toBool():
+        def xbool(x):
+            if isinstance(x, QVariant):
+                return x.toBool()
+            return bool(x)
+
+        if xbool(settings.get('advanced', False)):
             self.actions.advancedMode.setChecked(True)
             self.toggleAdvancedMode()
 
@@ -540,7 +594,7 @@ class MainWindow(QMainWindow, WindowMixin):
         else:
             shape = self.canvas.selectedShape
             if shape:
-                self.labelList.setItemSelected(self.shapesToItems[shape], True)
+                self.shapesToItems[shape].setSelected(True)
             else:
                 self.labelList.clearSelection()
         self.actions.delete.setEnabled(selected)
@@ -550,7 +604,7 @@ class MainWindow(QMainWindow, WindowMixin):
         self.actions.shapeFillColor.setEnabled(selected)
 
     def addLabel(self, shape):
-        item = QListWidgetItem(shape.label)
+        item = HashableQListWidgetItem(shape.label)
         item.setFlags(item.flags() | Qt.ItemIsUserCheckable)
         item.setCheckState(Qt.Checked)
         self.itemsToShapes[item] = shape
@@ -694,17 +748,16 @@ class MainWindow(QMainWindow, WindowMixin):
         self.resetState()
         self.canvas.setEnabled(False)
         if filename is None:
-            filename = self.settings['filename']
-        filename = filename
+            filename = self.settings.get('filename')
 
         # Tzutalin 20160906 : Add file list and dock to move faster
         # Highlight the file item
         if filename and self.fileListWidget.count() > 0:
             index = self.mImgList.index(filename)
             fileWidgetItem = self.fileListWidget.item(index)
-            self.fileListWidget.setItemSelected(fileWidgetItem, True)
+            fileWidgetItem.setSelected(True)
 
-        if QFile.exists(filename):
+        if filename and QFile.exists(filename):
             if LabelFile.isLabelFile(filename):
                 try:
                     self.labelFile = LabelFile(filename)
@@ -791,7 +844,7 @@ class MainWindow(QMainWindow, WindowMixin):
         s = self.settings
         # If it loads images from dir, don't load it at the begining
         if self.dirname is None:
-            s['filename'] = self.filename if self.filename else QString()
+            s['filename'] = self.filename if self.filename else ''
         else:
             s['filename'] = ''
 
@@ -967,7 +1020,6 @@ class MainWindow(QMainWindow, WindowMixin):
         dlg =  QFileDialog(self, caption, openDialogPath, filters)
         dlg.setDefaultSuffix(LabelFile.suffix[1:])
         dlg.setAcceptMode(QFileDialog.AcceptSave)
-        dlg.setConfirmOverwrite(True)
         filenameWithoutExtension = os.path.splitext(self.filename)[0]
         dlg.selectFile(filenameWithoutExtension)
         dlg.setOption(QFileDialog.DontUseNativeDialog, False)
@@ -1108,10 +1160,20 @@ class Settings(object):
 
     def _cast(self, key, value):
         # XXX: Very nasty way of converting types to QVariant methods :P
-        t = self.types[key]
-        if t != QVariant:
-            method = getattr(QVariant, re.sub('^Q', 'to', t.__name__, count=1))
-            return method(value)
+        print('_cast', key, repr(value))
+        t = self.types.get(key)
+        print('t', t)
+        if t is not None and t != QVariant:
+            if t is str:
+                return str(value)
+            else:
+                # XXX: awful
+                try:
+                    method = getattr(QVariant, re.sub('^Q', 'to', t.__name__, count=1))
+                    return method(value)
+                except AttributeError as e:
+                    print(e)
+                    return value
         return value
 
 
diff --git a/libs/canvas.py b/libs/canvas.py
index 1e76331c..b7e4aafd 100644
--- a/libs/canvas.py
+++ b/libs/canvas.py
@@ -1,5 +1,12 @@
-from PyQt4.QtGui import *
-from PyQt4.QtCore import *
+
+try:
+    from PyQt5.QtGui import *
+    from PyQt5.QtCore import *
+    from PyQt5.QtWidgets import *
+except ImportError:
+    from PyQt4.QtGui import *
+    from PyQt4.QtCore import *
+
 #from PyQt4.QtOpenGL import *
 
 from shape import Shape
@@ -85,7 +92,7 @@ class Canvas(QWidget):
 
     def mouseMoveEvent(self, ev):
         """Update line with last point and current coordinates."""
-        pos = self.transformPos(ev.posF())
+        pos = self.transformPos(ev.pos())
 
         self.restoreCursor()
 
@@ -169,7 +176,8 @@ class Canvas(QWidget):
             self.hVertex, self.hShape = None, None
 
     def mousePressEvent(self, ev):
-        pos = self.transformPos(ev.posF())
+        pos = self.transformPos(ev.pos())
+
         if ev.button() == Qt.LeftButton:
             if self.drawing():
                 if self.current and self.current.reachMaxPoints() is False:
diff --git a/libs/colorDialog.py b/libs/colorDialog.py
index 3e712f8a..8c0164a9 100644
--- a/libs/colorDialog.py
+++ b/libs/colorDialog.py
@@ -1,5 +1,10 @@
-from PyQt4.QtGui import *
-from PyQt4.QtCore import *
+try:
+    from PyQt5.QtGui import *
+    from PyQt5.QtCore import *
+    from PyQt5.QtWidgets import QColorDialog, QDialogButtonBox
+except ImportError:
+    from PyQt4.QtGui import *
+    from PyQt4.QtCore import *
 
 BB = QDialogButtonBox
 
diff --git a/libs/labelDialog.py b/libs/labelDialog.py
index 7f2b8992..c7f70575 100644
--- a/libs/labelDialog.py
+++ b/libs/labelDialog.py
@@ -1,5 +1,10 @@
-from PyQt4.QtGui import *
-from PyQt4.QtCore import *
+try:
+    from PyQt5.QtGui import *
+    from PyQt5.QtCore import *
+    from PyQt5.QtWidgets import *
+except ImportError:
+    from PyQt4.QtGui import *
+    from PyQt4.QtCore import *
 
 from lib import newIcon, labelValidator
 
@@ -32,11 +37,20 @@ class LabelDialog(QDialog):
         self.setLayout(layout)
 
     def validate(self):
-        if self.edit.text().trimmed():
-            self.accept()
+        try:
+            if self.edit.text().trimmed():
+                self.accept()
+        except AttributeError:
+            # PyQt5: AttributeError: 'str' object has no attribute 'trimmed'
+            if self.edit.text().strip():
+                self.accept()
 
     def postProcess(self):
-        self.edit.setText(self.edit.text().trimmed())
+        try:
+            self.edit.setText(self.edit.text().trimmed())
+        except AttributeError:
+            # PyQt5: AttributeError: 'str' object has no attribute 'trimmed'
+            self.edit.setText(self.edit.text())
 
     def popUp(self, text='', move=True):
         self.edit.setText(text)
@@ -47,6 +61,10 @@ class LabelDialog(QDialog):
         return self.edit.text() if self.exec_() else None
 
     def listItemClick(self, tQListWidgetItem):
-        text = tQListWidgetItem.text().trimmed()
+        try:
+            text = tQListWidgetItem.text().trimmed()
+        except AttributeError:
+            # PyQt5: AttributeError: 'str' object has no attribute 'trimmed'
+            text = tQListWidgetItem.text().strip()
         self.edit.setText(text)
         self.validate()
diff --git a/libs/labelFile.py b/libs/labelFile.py
index 2665d7f7..f4e490ce 100644
--- a/libs/labelFile.py
+++ b/libs/labelFile.py
@@ -1,7 +1,11 @@
 # Copyright (c) 2016 Tzutalin
 # Create by TzuTaLin <tzu.ta.lin@gmail.com>
 
-from PyQt4.QtGui import QImage
+try:
+    from PyQt5.QtGui import QImage
+except ImportError:
+    from PyQt4.QtGui import QImage
+
 from base64 import b64encode, b64decode
 from pascal_voc_io import PascalVocWriter
 import os.path
diff --git a/libs/lib.py b/libs/lib.py
index 821733b2..854309d7 100644
--- a/libs/lib.py
+++ b/libs/lib.py
@@ -1,7 +1,12 @@
 from math import sqrt
 
-from PyQt4.QtGui import *
-from PyQt4.QtCore import *
+try:
+    from PyQt5.QtGui import *
+    from PyQt5.QtCore import *
+    from PyQt5.QtWidgets import *
+except ImportError:
+    from PyQt4.QtGui import *
+    from PyQt4.QtCore import *
 
 
 def newIcon(icon):
diff --git a/libs/shape.py b/libs/shape.py
index 8f6c237f..317fd878 100644
--- a/libs/shape.py
+++ b/libs/shape.py
@@ -1,8 +1,13 @@
 #!/usr/bin/python
 # -*- coding: utf-8 -*-
 
-from PyQt4.QtGui import *
-from PyQt4.QtCore import *
+
+try:
+    from PyQt5.QtGui import *
+    from PyQt5.QtCore import *
+except ImportError:
+    from PyQt4.QtGui import *
+    from PyQt4.QtCore import *
 
 from lib import distance
 
diff --git a/libs/toolBar.py b/libs/toolBar.py
index c0f370d5..357f8e36 100644
--- a/libs/toolBar.py
+++ b/libs/toolBar.py
@@ -1,5 +1,11 @@
-from PyQt4.QtGui import *
-from PyQt4.QtCore import *
+try:
+    from PyQt5.QtGui import *
+    from PyQt5.QtCore import *
+    from PyQt5.QtWidgets import *
+except ImportError:
+    from PyQt4.QtGui import *
+    from PyQt4.QtCore import *
+
 
 class ToolBar(QToolBar):
     def __init__(self, title):
diff --git a/libs/zoomWidget.py b/libs/zoomWidget.py
index 7c3d160f..17c5b9f5 100644
--- a/libs/zoomWidget.py
+++ b/libs/zoomWidget.py
@@ -1,5 +1,10 @@
-from PyQt4.QtGui import *
-from PyQt4.QtCore import *
+try:
+    from PyQt5.QtGui import *
+    from PyQt5.QtCore import *
+    from PyQt5.QtWidgets import *
+except ImportError:
+    from PyQt4.QtGui import *
+    from PyQt4.QtCore import *
 
 class ZoomWidget(QSpinBox):
     def __init__(self, value=100):