diff --git a/python/core/geometry/qgsregularpolygon.sip b/python/core/geometry/qgsregularpolygon.sip
index 4294f02faad..b50671660ad 100644
--- a/python/core/geometry/qgsregularpolygon.sip
+++ b/python/core/geometry/qgsregularpolygon.sip
@@ -35,7 +35,7 @@ class QgsRegularPolygon
 
     QgsRegularPolygon();
 
-    QgsRegularPolygon( const QgsPoint &center, const double radius, const double azimuth, const int numberSides, const ConstructionOption circle );
+    QgsRegularPolygon( const QgsPoint &center, const double radius, const double azimuth, const unsigned int numberSides, const ConstructionOption circle );
 %Docstring
  Constructs a regular polygon by ``center`` and parameters for the first vertex. An empty regular polygon is returned if ``numberSides`` < 3 or ``ConstructionOption`` isn't valid.
  \param center The center of the regular polygon.
@@ -45,7 +45,7 @@ class QgsRegularPolygon
 .. seealso:: ConstructionOption
 %End
 
-    QgsRegularPolygon( const QgsPoint &center, const QgsPoint &pt1, const int  numberSides, const ConstructionOption circle );
+    QgsRegularPolygon( const QgsPoint &center, const QgsPoint &pt1, const unsigned int numberSides, const ConstructionOption circle );
 %Docstring
  Constructs a regular polygon by ``center`` and another point.
  \param center The center of the regular polygon.
@@ -54,7 +54,7 @@ class QgsRegularPolygon
  \param circle Option to create the polygon inscribed in circle (the radius is the distance between the center and vertices) or circumscribed about circle (the radius is the distance from the center to the midpoints of the sides).
 %End
 
-    QgsRegularPolygon( const QgsPoint &pt1, const QgsPoint &pt2, const int  numberSides );
+    QgsRegularPolygon( const QgsPoint &pt1, const QgsPoint &pt2, const unsigned int numberSides );
 %Docstring
  Constructs a regular polygon by two points of the first side.
  \param pt1 The first vertex of the first side, also first vertex of the regular polygon.
@@ -102,11 +102,10 @@ A regular polygon is empty if radius equal to 0 or number of sides < 3
  :rtype: float
 %End
 
-    int numberSides() const;
+    unsigned int numberSides() const;
 %Docstring
  Returns the number of sides of the regular polygon.
 .. seealso:: setNumberSides()
- :rtype: int
 %End
 
     void setCenter( const QgsPoint &center );
@@ -130,7 +129,7 @@ A regular polygon is empty if radius equal to 0 or number of sides < 3
 .. seealso:: firstVertex()
 %End
 
-    void setNumberSides( const int numberSides );
+    void setNumberSides( const unsigned int numberSides );
 %Docstring
  Sets the number of sides.
  If numberSides < 3, the number of sides is unchanged.
diff --git a/src/core/geometry/qgsregularpolygon.h b/src/core/geometry/qgsregularpolygon.h
index a4e5759e538..06bd82e6ade 100644
--- a/src/core/geometry/qgsregularpolygon.h
+++ b/src/core/geometry/qgsregularpolygon.h
@@ -60,7 +60,7 @@ class CORE_EXPORT QgsRegularPolygon
      * \param numberSides Number of sides of the regular polygon.
      * \param circle Option to create the polygon. \see ConstructionOption
      */
-    QgsRegularPolygon( const QgsPoint &center, const double radius, const double azimuth, const int numberSides, const ConstructionOption circle );
+    QgsRegularPolygon( const QgsPoint &center, const double radius, const double azimuth, const unsigned int numberSides, const ConstructionOption circle );
 
     /** Constructs a regular polygon by \a center and another point.
      * \param center The center of the regular polygon.
@@ -68,14 +68,14 @@ class CORE_EXPORT QgsRegularPolygon
      * \param numberSides Number of sides of the regular polygon.
      * \param circle Option to create the polygon inscribed in circle (the radius is the distance between the center and vertices) or circumscribed about circle (the radius is the distance from the center to the midpoints of the sides).
      */
-    QgsRegularPolygon( const QgsPoint &center, const QgsPoint &pt1, const int  numberSides, const ConstructionOption circle );
+    QgsRegularPolygon( const QgsPoint &center, const QgsPoint &pt1, const unsigned int numberSides, const ConstructionOption circle );
 
     /** Constructs a regular polygon by two points of the first side.
      * \param pt1 The first vertex of the first side, also first vertex of the regular polygon.
      * \param pt2 The second vertex of the first side.
      * \param numberSides Number of sides of the regular polygon.
      */
-    QgsRegularPolygon( const QgsPoint &pt1, const QgsPoint &pt2, const int  numberSides );
+    QgsRegularPolygon( const QgsPoint &pt1, const QgsPoint &pt2, const unsigned int numberSides );
 
     bool operator ==( const QgsRegularPolygon &rp ) const;
     bool operator !=( const QgsRegularPolygon &rp ) const;
@@ -109,7 +109,7 @@ class CORE_EXPORT QgsRegularPolygon
     /** Returns the number of sides of the regular polygon.
      * \see setNumberSides()
      */
-    int numberSides() const { return mNumberSides; }
+    unsigned int numberSides() const { return mNumberSides; }
 
     /** Sets the center point.
      * Radius is unchanged. The first vertex is reprojected from the new center.
@@ -133,7 +133,7 @@ class CORE_EXPORT QgsRegularPolygon
      * If numberSides < 3, the number of sides is unchanged.
      * \see numberSides()
      */
-    void setNumberSides( const int numberSides );
+    void setNumberSides( const unsigned int numberSides );
 
     /** Returns a list including the vertices of the regular polygon.
      */
diff --git a/tests/src/core/testqgsgeometry.cpp b/tests/src/core/testqgsgeometry.cpp
index 56424f04b3a..f9f610edbbc 100644
--- a/tests/src/core/testqgsgeometry.cpp
+++ b/tests/src/core/testqgsgeometry.cpp
@@ -4313,7 +4313,7 @@ void TestQgsGeometry::regularPolygon()
   QgsRegularPolygon rp1 = QgsRegularPolygon();
   QCOMPARE( rp1.center(), QgsPoint() );
   QCOMPARE( rp1.firstVertex(), QgsPoint() );
-  QCOMPARE( rp1.numberSides(), 0 );
+  QCOMPARE( rp1.numberSides(), static_cast< unsigned int >( 0 ) );
   QCOMPARE( rp1.radius(), 0.0 );
   QVERIFY( rp1.isEmpty() );
 
@@ -4327,7 +4327,7 @@ void TestQgsGeometry::regularPolygon()
   QVERIFY( !rp2.isEmpty() );
   QCOMPARE( rp2.center(), QgsPoint() );
   QCOMPARE( rp2.firstVertex(), QgsPoint( 0, 5 ) );
-  QCOMPARE( rp2.numberSides(), 5 );
+  QCOMPARE( rp2.numberSides(), static_cast< unsigned int>( 5 ) );
   QCOMPARE( rp2.radius(), 5.0 );
   QGSCOMPARENEAR( rp2.apothem(), 4.0451, 10E-4 );
   QVERIFY( rp2 ==  QgsRegularPolygon( QgsPoint(), -5, 0, 5, QgsRegularPolygon::InscribedCircle ) );
@@ -4367,16 +4367,16 @@ void TestQgsGeometry::regularPolygon()
 
   rp7.setNumberSides( 2 );
   QVERIFY( rp7.isEmpty() );
-  QCOMPARE( rp7.numberSides(), 0 );
+  QCOMPARE( rp7.numberSides(), static_cast< unsigned int >( 0 ) );
   rp7.setNumberSides( 5 );
   QVERIFY( rp7.isEmpty() );
-  QCOMPARE( rp7.numberSides(), 5 );
+  QCOMPARE( rp7.numberSides(), static_cast< unsigned int >( 5 ) );
   rp7.setNumberSides( 2 );
   QVERIFY( rp7.isEmpty() );
-  QCOMPARE( rp7.numberSides(), 5 );
+  QCOMPARE( rp7.numberSides(), static_cast< unsigned int >( 5 ) );
   rp7.setNumberSides( 3 );
   QVERIFY( rp7.isEmpty() );
-  QCOMPARE( rp7.numberSides(), 3 );
+  QCOMPARE( rp7.numberSides(), static_cast< unsigned int >( 3 ) );
 
   rp7.setRadius( -6 );
   QVERIFY( !rp7.isEmpty() );