On the standards track: Yes
Is Experimental: No
Is Deprecated: No
In Chrome version 4 on 2010-01-25 Note: Chrome ignores border-radius on <select> elements unless -webkit-appearance is overridden to an appropriate value.
In Chrome Android version 18 on 2012-06-27
In Edge version 12 on 2015-07-29
In Firefox version 4 on 2011-03-22 Note: Before Firefox 50, border styles of rounded corners (with border-radius) were always rendered as if border-style was solid. This has been fixed in Firefox 50. To conform to the CSS3 standard, Firefox 4 changes the handling of <percentage> values to match the specification. You can specify an ellipse as a border on an arbitrary sized element with border-radius: 50%;. Firefox 4 also makes rounded corners clip content and images if overflow: visible is not set.
In Firefox for Android version 4 on 2011-03-29 Note: Before Firefox 50, border styles of rounded corners (with border-radius) were always rendered as if border-style was solid. This has been fixed in Firefox 50.
In Internet Explorer version 9 on 2011-03-14
In Quest Browser version 5.0 on undefined
In Opera version 10.5 on 2010-03-02 Note: Before Opera 11.60, replaced elements with border-radius do not have rounded corners.
In Opera Android version 11 on 2011-03-22
In Safari version 5 on 2010-06-07 Note: Safari ignores border-radius on <select> elements unless -webkit-appearance is overridden to an appropriate value.
In Safari on iOS version 4.2 on 2010-11-22 Note: Safari ignores border-radius on <select> elements unless -webkit-appearance is overridden to an appropriate value.
In Samsung Internet version 1.0 on 2013-04-27
In WebView Android version ≤4.4 on undefined
In WebView on iOS version 4.2 on 2010-11-22 Note: Safari ignores border-radius on <select> elements unless -webkit-appearance is overridden to an appropriate value.