diff --git a/build.py b/build.py
index db866f8..3a4402b 100644
--- a/build.py
+++ b/build.py
@@ -246,7 +246,7 @@ def moduleChecks(maindir):
     # Check for the tqui library.
     if config.qt_version >= 0x030000:
         if sys.platform == "win32":
-            tquilib = r"$(QTDIR)\lib\tqui.lib"
+            tquilib = r"$(TQTDIR)\lib\tqui.lib"
         else:
             tquilib = "-ltqui"
 
@@ -578,7 +578,7 @@ def main(argv):
 
     if config.qt_version >= 0x030100:
         if sys.platform == "win32":
-            qaclib = r"$(QTDIR)\lib\qassistantclient.lib"
+            qaclib = r"$(TQTDIR)\lib\qassistantclient.lib"
         else:
             qaclib = "-lqassistantclient"
 
diff --git a/configure.py b/configure.py
index 133f1ae..39057b6 100644
--- a/configure.py
+++ b/configure.py
@@ -41,7 +41,7 @@ sip_min_version = 0x040800
 
 # Try and find a TQt installation to use as the default.
 try:
-    qt_dir = os.environ["QTDIR"]
+    qt_dir = os.environ["TQTDIR"]
 except KeyError:
     qt_dir = ""
 
@@ -1070,12 +1070,12 @@ def get_build_macros(overrides):
 
     # Add the TQt specific macros to the default.
     names = sipcfg.build_macros().keys()
-    names.append("INCDIR_QT")
-    names.append("LIBDIR_QT")
+    names.append("INCDIR_TQT")
+    names.append("LIBDIR_TQT")
     names.append("MOC")
 
-    # Make sure $QTDIR reflects any directory passed on the command line.
-    os.environ["QTDIR"] = qt_dir
+    # Make sure $TQTDIR reflects any directory passed on the command line.
+    os.environ["TQTDIR"] = qt_dir
 
     properties = {
         "QT_INSTALL_BINS":      os.path.join(qt_dir, "bin"),
@@ -1097,17 +1097,17 @@ def check_qt_installation(macros):
     # Set the TQt include and lib directories.
     global qt_incdir, qt_libdir
 
-    qt_incdir = macros["INCDIR_QT"]
+    qt_incdir = macros["INCDIR_TQT"]
 
     if not qt_incdir:
         qt_incdir = os.path.join(qt_dir, "include")
-        macros["INCDIR_QT"] = qt_incdir
+        macros["INCDIR_TQT"] = qt_incdir
 
-    qt_libdir = macros["LIBDIR_QT"]
+    qt_libdir = macros["LIBDIR_TQT"]
 
     if not qt_libdir:
         qt_libdir = os.path.join(qt_dir, "lib")
-        macros["LIBDIR_QT"] = qt_libdir
+        macros["LIBDIR_TQT"] = qt_libdir
 
     # Check the TQt header files have been installed.  Quietly check for TQt v4.
     qt4_d = os.path.join(qt_incdir, "TQtCore")
@@ -1399,7 +1399,7 @@ def main(argv):
 
     # Check that we know the name of the TQt root directory.
     if not qt_dir:
-        sipconfig.error("A TQt installation could not be found. Use use the -q argument or the QTDIR environment variable to explicitly specify the correct directory.")
+        sipconfig.error("A TQt installation could not be found. Use use the -q argument or the TQTDIR environment variable to explicitly specify the correct directory.")
 
     # When building static libraries, signed interpreter checking makes no
     # sense.
diff --git a/examples3/tablestatistics.py b/examples3/tablestatistics.py
index ee1f0f7..e0835bb 100755
--- a/examples3/tablestatistics.py
+++ b/examples3/tablestatistics.py
@@ -52,7 +52,7 @@ class Table(TQTable):
     def initTable(self):
         # read all the TQt source and header files into a list
         all = []
-        qtdir = os.getenv("QTDIR")
+        qtdir = os.getenv("TQTDIR")
         for i in dirs:
             dir = TQDir(os.path.join(qtdir, "src", i))
             lst = TQStringList(dir.entryList("*.cpp; *.h"))
diff --git a/pylupdate3/pylupdate.pro.in b/pylupdate3/pylupdate.pro.in
index 51f45a9..0a39857 100644
--- a/pylupdate3/pylupdate.pro.in
+++ b/pylupdate3/pylupdate.pro.in
@@ -23,7 +23,7 @@ SOURCES		= fetchtr.cpp \
 		  metatranslator.cpp \
 		  proparser.cpp
 
-rbprof:exists($(QTDIR)/src/qt_professional.pri) {
-	QT_SOURCE_TREE = $(QTDIR)
-	include($(QTDIR)/src/qt_professional.pri)
+rbprof:exists($(TQTDIR)/src/qt_professional.pri) {
+	QT_SOURCE_TREE = $(TQTDIR)
+	include($(TQTDIR)/src/qt_professional.pri)
 }
diff --git a/pyuic2/pyuic.pro.in b/pyuic2/pyuic.pro.in
index e81b138..beeea65 100644
--- a/pyuic2/pyuic.pro.in
+++ b/pyuic2/pyuic.pro.in
@@ -8,7 +8,7 @@
 
 TEMPLATE	= app
 CONFIG		= qt console warn_on release
-INCLUDEPATH	= @BLX_INCLUDEPATH@ $(QTDIR)/src/3rdparty/zlib
+INCLUDEPATH	= @BLX_INCLUDEPATH@ $(TQTDIR)/src/3rdparty/zlib
 DEFINES		= UIC @BLX_DEFINES@
 
 DESTDIR		= @PYQT_BINDIR@
diff --git a/pyuic3/pyuic.pro.in b/pyuic3/pyuic.pro.in
index 7b5b911..5c9b3e8 100644
--- a/pyuic3/pyuic.pro.in
+++ b/pyuic3/pyuic.pro.in
@@ -8,7 +8,7 @@
 
 TEMPLATE	= app
 CONFIG		+= qt console warn_on release @PYQT_RBPROF@
-INCLUDEPATH	+= @BLX_INCLUDEPATH@ $(QTDIR)/src/3rdparty/zlib
+INCLUDEPATH	+= @BLX_INCLUDEPATH@ $(TQTDIR)/src/3rdparty/zlib
 DEFINES		+= UIC QT_INTERNAL_XML @BLX_DEFINES@
 
 DESTDIR		= @PYQT_BINDIR@
@@ -30,7 +30,7 @@ SOURCES		= main.cpp \
 		  domtool.cpp \
 		  parser.cpp
 
-rbprof:exists($(QTDIR)/src/qt_professional.pri) {
-	QT_SOURCE_TREE = $(QTDIR)
-	include($(QTDIR)/src/qt_professional.pri)
+rbprof:exists($(TQTDIR)/src/qt_professional.pri) {
+	QT_SOURCE_TREE = $(TQTDIR)
+	include($(TQTDIR)/src/qt_professional.pri)
 }