diff --git a/src/widgets/widgets/qprogressbar.cpp b/src/widgets/widgets/qprogressbar.cpp
index 72e937b604..6b3dadddf0 100644
--- a/src/widgets/widgets/qprogressbar.cpp
+++ b/src/widgets/widgets/qprogressbar.cpp
@@ -41,6 +41,7 @@
 
 #include "qprogressbar.h"
 #ifndef QT_NO_PROGRESSBAR
+#include <qlocale.h>
 #include <qevent.h>
 #include <qpainter.h>
 #include <qstylepainter.h>
@@ -61,6 +62,7 @@ public:
     QProgressBarPrivate();
 
     void init();
+    void initDefaultFormat();
     inline void resetLayoutItemMargins();
 
     int minimum;
@@ -68,6 +70,7 @@ public:
     int value;
     Qt::Alignment alignment;
     uint textVisible : 1;
+    uint defaultFormat: 1;
     int lastPaintedValue;
     Qt::Orientation orientation;
     bool invertedAppearance;
@@ -79,9 +82,16 @@ public:
 
 QProgressBarPrivate::QProgressBarPrivate()
     : minimum(0), maximum(100), value(-1), alignment(Qt::AlignLeft), textVisible(true),
-      lastPaintedValue(-1), orientation(Qt::Horizontal), invertedAppearance(false),
-      textDirection(QProgressBar::TopToBottom), format(QLatin1String("%p%"))
+      defaultFormat(true), lastPaintedValue(-1), orientation(Qt::Horizontal), invertedAppearance(false),
+      textDirection(QProgressBar::TopToBottom)
 {
+    initDefaultFormat();
+}
+
+void QProgressBarPrivate::initDefaultFormat()
+{
+    if (defaultFormat)
+        format = QLatin1String("%p") + locale.percent();
 }
 
 void QProgressBarPrivate::init()
@@ -466,19 +476,21 @@ QString QProgressBar::text() const
     qint64 totalSteps = qint64(d->maximum) - d->minimum;
 
     QString result = d->format;
-    result.replace(QLatin1String("%m"), QString::number(totalSteps));
-    result.replace(QLatin1String("%v"), QString::number(d->value));
+    QLocale locale = d->locale; // Omit group separators for compatibility with previous versions that were non-localized.
+    locale.setNumberOptions(locale.numberOptions() | QLocale::OmitGroupSeparator);
+    result.replace(QLatin1String("%m"), locale.toString(totalSteps));
+    result.replace(QLatin1String("%v"), locale.toString(d->value));
 
     // If max and min are equal and we get this far, it means that the
     // progress bar has one step and that we are on that step. Return
     // 100% here in order to avoid division by zero further down.
     if (totalSteps == 0) {
-        result.replace(QLatin1String("%p"), QString::number(100));
+        result.replace(QLatin1String("%p"), locale.toString(int(100)));
         return result;
     }
 
     int progress = (qreal(d->value) - d->minimum) * 100.0 / totalSteps;
-    result.replace(QLatin1String("%p"), QString::number(progress));
+    result.replace(QLatin1String("%p"), locale.toString(progress));
     return result;
 }
 
@@ -568,12 +580,19 @@ QProgressBar::Direction QProgressBar::textDirection() const
 bool QProgressBar::event(QEvent *e)
 {
     Q_D(QProgressBar);
-    if (e->type() == QEvent::StyleChange
+    switch (e->type()) {
+    case QEvent::StyleChange:
 #ifdef Q_OS_MAC
-            || e->type() == QEvent::MacSizeChange
+    case QEvent::MacSizeChange:
 #endif
-            )
         d->resetLayoutItemMargins();
+        break;
+    case QEvent::LocaleChange:
+        d->initDefaultFormat();
+        break;
+    default:
+        break;
+    }
     return QWidget::event(e);
 }
 
@@ -596,6 +615,15 @@ void QProgressBar::setFormat(const QString &format)
     if (d->format == format)
         return;
     d->format = format;
+    d->defaultFormat = false;
+    update();
+}
+
+void QProgressBar::resetFormat()
+{
+    Q_D(QProgressBar);
+    d->defaultFormat = true;
+    d->initDefaultFormat();
     update();
 }
 
diff --git a/src/widgets/widgets/qprogressbar.h b/src/widgets/widgets/qprogressbar.h
index 99fbe005ed..71bb2fc8f8 100644
--- a/src/widgets/widgets/qprogressbar.h
+++ b/src/widgets/widgets/qprogressbar.h
@@ -65,7 +65,7 @@ class Q_WIDGETS_EXPORT QProgressBar : public QWidget
     Q_PROPERTY(Qt::Orientation orientation READ orientation WRITE setOrientation)
     Q_PROPERTY(bool invertedAppearance READ invertedAppearance WRITE setInvertedAppearance)
     Q_PROPERTY(Direction textDirection READ textDirection WRITE setTextDirection)
-    Q_PROPERTY(QString format READ format WRITE setFormat)
+    Q_PROPERTY(QString format READ format WRITE setFormat RESET resetFormat)
 
 public:
     enum Direction { TopToBottom, BottomToTop };
@@ -96,6 +96,7 @@ public:
     QProgressBar::Direction textDirection() const;
 
     void setFormat(const QString &format);
+    void resetFormat();
     QString format() const;
 
 public Q_SLOTS:
diff --git a/tests/auto/widgets/widgets/qprogressbar/tst_qprogressbar.cpp b/tests/auto/widgets/widgets/qprogressbar/tst_qprogressbar.cpp
index 5ad9aa7690..2bbfb48e63 100644
--- a/tests/auto/widgets/widgets/qprogressbar/tst_qprogressbar.cpp
+++ b/tests/auto/widgets/widgets/qprogressbar/tst_qprogressbar.cpp
@@ -42,6 +42,7 @@
 
 #include <QtTest/QtTest>
 #include "qprogressbar.h"
+#include <qlocale.h>
 #include <qapplication.h>
 #include <qstyleoption.h>
 #include <qdebug.h>
@@ -64,6 +65,7 @@ private slots:
     void sizeHint();
     void formatedText_data();
     void formatedText();
+    void localizedFormattedText();
 
     void task245201_testChangeStyleAndDelete_data();
     void task245201_testChangeStyleAndDelete();
@@ -301,6 +303,40 @@ void tst_QProgressBar::formatedText()
     QCOMPARE(bar.text(), text);
 }
 
+void tst_QProgressBar::localizedFormattedText() // QTBUG-28751
+{
+    QProgressBar bar;
+    const int value = 42;
+    bar.setValue(value);
+    const QString defaultExpectedNumber = QString::number(value);
+    const QString defaultExpectedValue = defaultExpectedNumber + QLatin1Char('%');
+    QCOMPARE(bar.text(), defaultExpectedValue);
+
+    // Temporarily switch to Egyptian, which has a different percent sign and number formatting
+    QLocale egypt(QLocale::Arabic, QLocale::Egypt);
+    bar.setLocale(egypt);
+    const QString egyptianExpectedNumber = egypt.toString(value);
+    const QString egyptianExpectedValue = egyptianExpectedNumber + egypt.percent();
+    if (egyptianExpectedValue == defaultExpectedValue)
+        QSKIP("Egyptian locale does not work on this system.");
+    QCOMPARE(bar.text(), egyptianExpectedValue);
+
+    bar.setLocale(QLocale());
+    QCOMPARE(bar.text(), defaultExpectedValue);
+
+    // Set a custom format containing only the number
+    bar.setFormat(QStringLiteral("%p"));
+    QCOMPARE(bar.text(), defaultExpectedNumber);
+    bar.setLocale(egypt);
+    QCOMPARE(bar.text(), egyptianExpectedNumber);
+
+    // Clear the format
+    bar.resetFormat();
+    QCOMPARE(bar.text(), egyptianExpectedValue);
+    bar.setLocale(QLocale());
+    QCOMPARE(bar.text(), defaultExpectedValue);
+}
+
 void tst_QProgressBar::task245201_testChangeStyleAndDelete_data()
 {
     QTest::addColumn<QString>("style1_str");