It’s matte. After trying out several different prototypes, we've found that a matte surface is best. We quickly found that there were some disadvantages with a glossy surface. The first disadvantage was that a glossy surface led to increased sweat on our hands. The second disadvantage was that you have very little grip and the mouse tends to slip off. Also, if it was a polished glossy surface, each small scratch could be seen, and micro scratches inevitably happen in your day-to-day usage. We eventually decided to go with a matte surface for our mice and we're really happy with the decision. The matte surface provides a good grip and doesn't show scratches as much.