In this article, I introduce and analyze the notion of joint abilities; a species of ability possessed by agents who perform joint actions of a certain kind (or kinds). Joint abilities are abilities possessed by individual agents; however, they are possessed jointly. I also introduce and analyze an important species of joint abilities, namely, joint epistemic abilities - the exercise of which consists of joint epistemic action. (I also distinguish joint epistemic abilities from the related notion of joint know-how.) Joint epistemic actions yield collective knowledge of various kinds and many, but by no means all, joint epistemic actions consist of the exercise of joint epistemic abilities. Joint epistemic abilities are an important phenomenon since, it turns out, they underpin a good deal of collective knowledge, including a good deal of scientific knowledge. Finally, I address some problems that arise for my notion of joint epistemic abilities.