diff --git a/src/plugins/qtsupport/baseqtversion.cpp b/src/plugins/qtsupport/baseqtversion.cpp
index ddf6ba6cf0b..682357fcbf9 100644
--- a/src/plugins/qtsupport/baseqtversion.cpp
+++ b/src/plugins/qtsupport/baseqtversion.cpp
@@ -488,7 +488,7 @@ QString BaseQtVersion::designerCommand() const
     if (!isValid())
         return QString();
     if (m_designerCommand.isNull())
-        m_designerCommand = findQtBinary(possibleGuiBinaries(QLatin1String("designer")));
+        m_designerCommand = findQtBinary(Designer);
     return m_designerCommand;
 }
 
@@ -497,7 +497,7 @@ QString BaseQtVersion::linguistCommand() const
     if (!isValid())
         return QString();
     if (m_linguistCommand.isNull())
-        m_linguistCommand = findQtBinary(possibleGuiBinaries(QLatin1String("linguist")));
+        m_linguistCommand = findQtBinary(Linguist);
     return m_linguistCommand;
 }
 
@@ -506,27 +506,67 @@ QString BaseQtVersion::qmlviewerCommand() const
     if (!isValid())
         return QString();
 
-    if (m_qmlviewerCommand.isNull()) {
-#ifdef Q_OS_MAC
-        const QString qmlViewerName = QLatin1String("QMLViewer");
-#else
-        const QString qmlViewerName = QLatin1String("qmlviewer");
-#endif
-
-        m_qmlviewerCommand = findQtBinary(possibleGuiBinaries(qmlViewerName));
-    }
+    if (m_qmlviewerCommand.isNull())
+        m_qmlviewerCommand = findQtBinary(QmlViewer);
     return m_qmlviewerCommand;
 }
 
-QString BaseQtVersion::findQtBinary(const QStringList &possibleCommands) const
+QString BaseQtVersion::findQtBinary(BINARIES binary) const
 {
-    QString qtdirbin = versionInfo().value(QLatin1String("QT_INSTALL_BINS"));
-    if (qtdirbin.isEmpty())
-        return QString();
-    qtdirbin += QLatin1Char('/');
+    QString baseDir;
+    if (qtVersion() < QtVersionNumber(5, 0, 0)) {
+        baseDir = versionInfo().value(QLatin1String("QT_INSTALL_BINS"));
+    } else {
+        ensureMkSpecParsed();
+        switch (binary) {
+        case QmlViewer:
+            baseDir = m_mkspecValues.value("QT.declarative.bins");
+            break;
+        case Designer:
+        case Linguist:
+            baseDir = m_mkspecValues.value("QT.designer.bins");
+            break;
+        case Uic:
+            baseDir = versionInfo().value(QLatin1String("QT_INSTALL_BINS"));
+            break;
+        default:
+            // Can't happen
+            Q_ASSERT(false);
+        }
+    }
 
+    if (baseDir.isEmpty())
+        return QString();
+    if (!baseDir.endsWith('/'))
+        baseDir += QLatin1Char('/');
+
+    QStringList possibleCommands;
+    switch (binary) {
+    case QmlViewer:
+#ifdef Q_OS_MAC
+        possibleCommands << QLatin1String("QMLViewer");
+#else
+        possibleCommands << QLatin1String("qmlviewer");
+#endif
+        break;
+    case Designer:
+        possibleCommands << possibleGuiBinaries(QLatin1String("designer"));
+        break;
+    case Linguist:
+        possibleCommands << possibleGuiBinaries(QLatin1String("linguist"));
+        break;
+    case Uic:
+#ifdef Q_OS_WIN
+        possibleCommands << QLatin1String("uic.exe");
+#else
+        possibleCommands << QLatin1String("uic-qt4") << QLatin1String("uic4") << QLatin1String("uic");
+#endif
+        break;
+    default:
+        Q_ASSERT(false);
+    }
     foreach (const QString &possibleCommand, possibleCommands) {
-        const QString fullPath = qtdirbin + possibleCommand;
+        const QString fullPath = baseDir + possibleCommand;
         if (QFileInfo(fullPath).isFile())
             return QDir::cleanPath(fullPath);
     }
@@ -539,13 +579,7 @@ QString BaseQtVersion::uicCommand() const
         return QString();
     if (!m_uicCommand.isNull())
         return m_uicCommand;
-#ifdef Q_OS_WIN
-    const QStringList possibleCommands(QLatin1String("uic.exe"));
-#else
-    QStringList possibleCommands;
-    possibleCommands << QLatin1String("uic-qt4") << QLatin1String("uic4") << QLatin1String("uic");
-#endif
-    m_uicCommand = findQtBinary(possibleCommands);
+    m_uicCommand = findQtBinary(Uic);
     return m_uicCommand;
 }
 
@@ -625,6 +659,9 @@ void BaseQtVersion::parseMkSpec(ProFileEvaluator *evaluator) const
         else if (value == "build_all")
             m_defaultConfigIsDebugAndRelease = true;
     }
+
+    m_mkspecValues.insert("QT.designer.bins", evaluator->value("QT.designer.bins"));
+    m_mkspecValues.insert("QT.declarative.bins", evaluator->value("QT.declarative.bins"));
 }
 
 QString BaseQtVersion::mkspec() const
diff --git a/src/plugins/qtsupport/baseqtversion.h b/src/plugins/qtsupport/baseqtversion.h
index 7f6ee164feb..afbb7aacbbe 100644
--- a/src/plugins/qtsupport/baseqtversion.h
+++ b/src/plugins/qtsupport/baseqtversion.h
@@ -228,7 +228,8 @@ private:
     void ctor(const QString &qmakePath);
     void updateSourcePath() const;
     void updateVersionInfo() const;
-    QString findQtBinary(const QStringList &possibleName) const;
+    enum BINARIES { QmlViewer, Designer, Linguist, Uic };
+    QString findQtBinary(BINARIES binary) const;
     void updateMkspec() const;
     void setId(int id); // used by the qtversionmanager for legacy restore
                         // and by the qtoptionspage to replace qt versions
@@ -250,6 +251,7 @@ private:
     mutable bool m_mkspecReadUpToDate;
     mutable bool m_defaultConfigIsDebug;
     mutable bool m_defaultConfigIsDebugAndRelease;
+    mutable QHash<QString, QString> m_mkspecValues;
 
     mutable bool m_versionInfoUpToDate;
     mutable QHash<QString,QString> m_versionInfo;