diff --git a/pkgs/applications/misc/merkaartor/default.nix b/pkgs/applications/misc/merkaartor/default.nix
index 3023a5b5930c..149546e46d2f 100644
--- a/pkgs/applications/misc/merkaartor/default.nix
+++ b/pkgs/applications/misc/merkaartor/default.nix
@@ -1,5 +1,5 @@
 { stdenv, fetchFromGitHub, makeWrapper, qmake, pkgconfig, boost, gdal, proj
-, qtbase, qtsvg, qtwebkit }:
+, qtbase, qtsvg, qtwebview, qtwebkit }:
 
 stdenv.mkDerivation rec {
   pname = "merkaartor";
@@ -14,7 +14,7 @@ stdenv.mkDerivation rec {
 
   nativeBuildInputs = [ makeWrapper qmake pkgconfig ];
 
-  buildInputs = [ boost gdal proj qtbase qtsvg qtwebkit ];
+  buildInputs = [ boost gdal proj qtbase qtsvg qtwebview qtwebkit ];
 
   enableParallelBuilding = true;
 
@@ -30,5 +30,6 @@ stdenv.mkDerivation rec {
     homepage = http://merkaartor.be/;
     license = licenses.gpl2Plus;
     maintainers = with maintainers; [ ];
+    broken = true;  # Does not build with qt >= 5.12
   };
 }
diff --git a/pkgs/applications/version-management/bcompare/default.nix b/pkgs/applications/version-management/bcompare/default.nix
index 8f862af0a282..d8a6ec058448 100644
--- a/pkgs/applications/version-management/bcompare/default.nix
+++ b/pkgs/applications/version-management/bcompare/default.nix
@@ -1,4 +1,4 @@
-{ autoPatchelfHook, bzip2, cairo, coreutils, fetchurl, gdk-pixbuf, gnome2, gtk2, kcoreaddons, ki18n, kio, kservice, lib, qt4, qt511, qtbase, stdenv, runtimeShell }:
+{ autoPatchelfHook, bzip2, cairo, coreutils, fetchurl, gdk-pixbuf, gnome2, gtk2, kcoreaddons, ki18n, kio, kservice, lib, qt4, qtbase, stdenv, runtimeShell }:
 
 stdenv.mkDerivation rec {
   pname = "bcompare";
diff --git a/pkgs/development/ruby-modules/gem-config/default.nix b/pkgs/development/ruby-modules/gem-config/default.nix
index d8c3d484f436..18e24d5a31ed 100644
--- a/pkgs/development/ruby-modules/gem-config/default.nix
+++ b/pkgs/development/ruby-modules/gem-config/default.nix
@@ -21,7 +21,7 @@
 , libiconv, postgresql, v8, clang, sqlite, zlib, imagemagick
 , pkgconfig , ncurses, xapian, gpgme, utillinux, tzdata, icu, libffi
 , cmake, libssh2, openssl, libmysqlclient, darwin, git, perl, pcre, gecode_3, curl
-, msgpack, qt59, libsodium, snappy, libossp_uuid, lxc, libpcap, xorg, gtk2, buildRubyGem
+, msgpack, libsodium, snappy, libossp_uuid, lxc, libpcap, xorg, gtk2, buildRubyGem
 , cairo, re2, rake, gobject-introspection, gdk-pixbuf, zeromq, czmq, graphicsmagick, libcxx
 , file, libvirt, glib, vips, taglib, libopus, linux-pam, libidn, protobuf, fribidi, harfbuzz
 , bison, flex, pango, python3, patchelf, binutils, freetds, wrapGAppsHook, atk
@@ -70,11 +70,6 @@ in
     buildInputs = [ cairo pcre xorg.libpthreadstubs xorg.libXdmcp ];
   };
 
-  capybara-webkit = attrs: {
-    buildInputs = [ qt59.qtbase qt59.qtwebkit ] ++ stdenv.lib.optionals stdenv.isDarwin [ darwin.apple_sdk.frameworks.Cocoa ];
-    NIX_CFLAGS_COMPILE = stdenv.lib.optionalString stdenv.isDarwin "-I${libcxx}/include/c++/v1";
-  };
-
   charlock_holmes = attrs: {
     buildInputs = [ which icu zlib ];
   };
diff --git a/pkgs/tools/graphics/nifskope/default.nix b/pkgs/tools/graphics/nifskope/default.nix
index 0e545fbfab9f..90716d04a75a 100644
--- a/pkgs/tools/graphics/nifskope/default.nix
+++ b/pkgs/tools/graphics/nifskope/default.nix
@@ -1,4 +1,4 @@
-{ stdenv, fetchFromGitHub, qmake, qtbase, qttools, substituteAll, libGLU, wrapQtAppsHook }:
+{ stdenv, fetchFromGitHub, qmake, qtbase, qttools, substituteAll, libGLU, wrapQtAppsHook, fetchpatch }:
 
 stdenv.mkDerivation {
   pname = "nifskope";
@@ -18,6 +18,11 @@ stdenv.mkDerivation {
       src = ./qttools-bins.patch;
       qttools = "${qttools.dev}/bin";
     })
+    (fetchpatch {
+      name = "qt512-build-fix.patch";
+      url = "https://github.com/niftools/nifskope/commit/30954e7f01f3d779a2a1fd37d363e8a6ad560bd3.patch";
+      sha256 = "0d6xjj2mjjhdd7w1aig5f75jksjni16jyj0lxsz51pys6xqb6fpj";
+    })
   ];
 
   buildInputs = [ qtbase qttools libGLU.dev ];
diff --git a/pkgs/top-level/all-packages.nix b/pkgs/top-level/all-packages.nix
index be48819fe15c..8a03c1ee5507 100644
--- a/pkgs/top-level/all-packages.nix
+++ b/pkgs/top-level/all-packages.nix
@@ -5213,7 +5213,7 @@ in
 
   niff = callPackage ../tools/package-management/niff { };
 
-  nifskope = libsForQt59.callPackage ../tools/graphics/nifskope { };
+  nifskope = libsForQt5.callPackage ../tools/graphics/nifskope { };
 
   nilfs-utils = callPackage ../tools/filesystems/nilfs-utils {};
 
@@ -9853,7 +9853,7 @@ in
 
   funnelweb = callPackage ../development/tools/literate-programming/funnelweb { };
 
-  gede = libsForQt59.callPackage ../development/tools/misc/gede { };
+  gede = libsForQt5.callPackage ../development/tools/misc/gede { };
 
   gdbgui = python3Packages.callPackage ../development/tools/misc/gdbgui { };
 
@@ -13482,10 +13482,7 @@ in
 
   python-qt = callPackage ../development/libraries/python-qt {
     python = python27;
-    qmake = qt59.qmake;
-    qttools = qt59.qttools;
-    qtwebengine = qt59.qtwebengine;
-    qtxmlpatterns = qt59.qtxmlpatterns;
+    inherit (qt5) qmake qttools qtwebengine qtxmlpatterns;
   };
 
   pyotherside = libsForQt5.callPackage ../development/libraries/pyotherside {};
@@ -18164,7 +18161,7 @@ in
     pygments = python27Packages.pygments;
   };
 
-  csound-qt = libsForQt59.callPackage ../applications/audio/csound/csound-qt {
+  csound-qt = libsForQt5.callPackage ../applications/audio/csound/csound-qt {
     python = python27;
   };
 
@@ -19853,7 +19850,7 @@ in
 
   mercurialFull = appendToName "full" (pkgs.mercurial.override { guiSupport = true; });
 
-  merkaartor = libsForQt59.callPackage ../applications/misc/merkaartor {
+  merkaartor = libsForQt5.callPackage ../applications/misc/merkaartor {
     gdal = gdal_2; # https://github.com/openstreetmap/merkaartor/issues/179
   };
 
@@ -20562,7 +20559,7 @@ in
     gtksharp = gtk-sharp-2_0;
   };
 
-  plex-media-player = libsForQt59.callPackage ../applications/video/plex-media-player { };
+  plex-media-player = libsForQt5.callPackage ../applications/video/plex-media-player { };
 
   plover = recurseIntoAttrs (libsForQt5.callPackage ../applications/misc/plover { });
 
@@ -22462,7 +22459,7 @@ in
 
   chessdb = callPackage ../games/chessdb { };
 
-  chessx = libsForQt59.callPackage ../games/chessx { };
+  chessx = libsForQt5.callPackage ../games/chessx { };
 
   chiaki = libsForQt5.callPackage ../games/chiaki { };