Comment by jasallen

Microsoft's Xamarin Forms 3.0 (stable release later this year) allows you to target Linux and Mac[1] and is very similar to UWP conceptually - UI written once, run anywhere. It's just that Xamarin's "anywhere" is much larger :)

Disclosure: I work on Xamarin team at Microsoft

[1]https://forums.xamarin.com/discussion/85747/xamarin-forms-fe...