diff --git a/src/core/geometry/qgsrectangle.cpp b/src/core/geometry/qgsrectangle.cpp
index 67cc65fa4ab9..136cee7629a7 100644
--- a/src/core/geometry/qgsrectangle.cpp
+++ b/src/core/geometry/qgsrectangle.cpp
@@ -34,19 +34,24 @@
 QgsRectangle QgsRectangle::fromWkt( const QString &wkt )
 {
   const QgsGeometry geom = QgsGeometry::fromWkt( wkt );
-  if ( geom.isMultipart() )
+  if ( geom.isEmpty() )
     return QgsRectangle();
 
-  const QgsPolygonXY poly = geom.asPolygon();
-
-  if ( poly.size() != 1 )
-    return QgsRectangle();
+  if ( const QgsPolygon *polygon = qgsgeometry_cast< const QgsPolygon * >( geom.constGet()->simplifiedTypeRef() ) )
+  {
+    if ( polygon->numInteriorRings() > 0 )
+      return QgsRectangle();
 
-  const QgsPolylineXY polyline = geom.asPolygon().at( 0 );
-  if ( polyline.size() == 5 && polyline.at( 0 ) == polyline.at( 4 ) && geom.isGeosValid() )
-    return QgsRectangle( polyline.at( 0 ).x(), polyline.at( 0 ).y(), polyline.at( 2 ).x(), polyline.at( 2 ).y() );
-  else
-    return QgsRectangle();
+    if ( const QgsLineString *exterior = qgsgeometry_cast< QgsLineString * >( polygon->exteriorRing() ) )
+    {
+      if ( exterior->numPoints() == 5
+           && qgsDoubleNear( exterior->xAt( 0 ), exterior->xAt( 4 ) )
+           && qgsDoubleNear( exterior->yAt( 0 ), exterior->yAt( 4 ) )
+           && geom.isGeosValid() )
+        return QgsRectangle( exterior->xAt( 0 ), exterior->yAt( 0 ), exterior->xAt( 2 ), exterior->yAt( 2 ) );
+    }
+  }
+  return QgsRectangle();
 }
 
 QgsRectangle QgsRectangle::fromCenterAndSize( const QgsPointXY &center, double width, double height )
diff --git a/tests/src/core/geometry/testqgsrectangle.cpp b/tests/src/core/geometry/testqgsrectangle.cpp
index 0db9d048a212..571051c0c9be 100644
--- a/tests/src/core/geometry/testqgsrectangle.cpp
+++ b/tests/src/core/geometry/testqgsrectangle.cpp
@@ -80,7 +80,7 @@ void TestQgsRectangle::isNull()
 
 void TestQgsRectangle::fromWkt()
 {
-  const QgsRectangle rect = QgsRectangle::fromWkt( QStringLiteral( "POLYGON((0 0,1 0,1 1,0 1,0 0))" ) );
+  QgsRectangle rect = QgsRectangle::fromWkt( QStringLiteral( "POLYGON((0 0,1 0,1 1,0 1,0 0))" ) );
   QVERIFY( ! rect.isEmpty() );
   QCOMPARE( rect.xMinimum(), 0.0 );
   QCOMPARE( rect.yMinimum(), 0.0 );
@@ -89,6 +89,36 @@ void TestQgsRectangle::fromWkt()
 
   QVERIFY( rect == QgsRectangle::fromWkt( rect.asWktPolygon() ) );
 
+  rect = QgsRectangle::fromWkt( QStringLiteral( "POLYGONZ((0 0 2,1 0 2,1 1 2,0 1 2,0 0 2))" ) );
+  QVERIFY( ! rect.isEmpty() );
+  QCOMPARE( rect.xMinimum(), 0.0 );
+  QCOMPARE( rect.yMinimum(), 0.0 );
+  QCOMPARE( rect.xMaximum(), 1.0 );
+  QCOMPARE( rect.yMaximum(), 1.0 );
+
+  QVERIFY( rect == QgsRectangle::fromWkt( rect.asWktPolygon() ) );
+
+  // this is ok, a single rectangular polygon in a multipolygon object
+  rect = QgsRectangle::fromWkt( QStringLiteral( "MULTIPOLYGON(((0 0,1 0,1 1,0 1,0 0)))" ) );
+  QVERIFY( ! rect.isEmpty() );
+  QCOMPARE( rect.xMinimum(), 0.0 );
+  QCOMPARE( rect.yMinimum(), 0.0 );
+  QCOMPARE( rect.xMaximum(), 1.0 );
+  QCOMPARE( rect.yMaximum(), 1.0 );
+  QVERIFY( rect == QgsRectangle::fromWkt( rect.asWktPolygon() ) );
+
+  // this is ok, a single rectangular polygon in a collection
+  rect = QgsRectangle::fromWkt( QStringLiteral( "GEOMETRYCOLLECTION(MULTIPOLYGON(((0 0,1 0,1 1,0 1,0 0))))" ) );
+  QVERIFY( ! rect.isEmpty() );
+  QCOMPARE( rect.xMinimum(), 0.0 );
+  QCOMPARE( rect.yMinimum(), 0.0 );
+  QCOMPARE( rect.xMaximum(), 1.0 );
+  QCOMPARE( rect.yMaximum(), 1.0 );
+  QVERIFY( rect == QgsRectangle::fromWkt( rect.asWktPolygon() ) );
+
+  QVERIFY( QgsRectangle::fromWkt( QStringLiteral( "xxx" ) ).isEmpty() );
+  QVERIFY( QgsRectangle::fromWkt( QStringLiteral( "LINESTRING ()" ) ).isEmpty() );
+  QVERIFY( QgsRectangle::fromWkt( QStringLiteral( "MULTIPOLYGON()" ) ).isEmpty() );
   QVERIFY( QgsRectangle::fromWkt( QStringLiteral( "LINESTRING (0 0,1 0,1 1,0 1,0 0)" ) ).isEmpty() );
   QVERIFY( QgsRectangle::fromWkt( QStringLiteral( "MULTIPOLYGON(((0 0,3 0,3 3,0 3,0 0)),((1 1, 1 2, 2 2, 2 1)))" ) ).isEmpty() );
   QVERIFY( QgsRectangle::fromWkt( QStringLiteral( "MULTIPOLYGON(((0 0,3 0,3 3,0 3,0 0), (10 10,13 10,13 13,10 13,10 10)))" ) ).isEmpty() );