Answer : 1. Solution Summary You can use shape for FlatButton and RaisedButton . 2. Rounded Button shape: RoundedRectangleBorder( borderRadius: BorderRadius.circular(18.0), side: BorderSide(color: Colors.red) ), Square Button shape: RoundedRectangleBorder( borderRadius: BorderRadius.zero, side: BorderSide(color: Colors.red) ), Complete Example Row( mainAxisAlignment: MainAxisAlignment.end, children: <Widget>[ FlatButton( shape: RoundedRectangleBorder( borderRadius: BorderRadius.circular(18.0), side: BorderSide(color: Colors.red)), color: Colors.white, textColor: Colors.red, padding: EdgeInsets.all(8.0), onPressed: () {}, child: Text( "Add to Cart".toUpperCase(), style: TextStyle( fontSize: 14.0, ), ), ), SizedBox(width: 10), RaisedButton( shape: RoundedRectangleBorder( borderRadius: BorderRadius.circular(18.0), side: BorderSi