Knowledge transfer across different contexts has become an increasingly prevalent feature of current science. As such, it is a relevant topic also for history and philosophy of science. This special issue presents a set of papers that study knowledge transfer in various disciplines. The contributions approach the topic from either an integrated history and philosophy of science perspective, 2) a systematic philosophical perspective, or 3) a historical perspective. This overview article is organized in three sections. The introduction provides some background and context of the topic. The second section specifies the three components of knowledge transfer, i.e., knowledge, context, and the transfer process. It motivates our take on this topic and then outlines the central ideas of each paper. The third section reflects on the kinds of methods used to study processes of knowledge transfer. The article concludes by highlighting some of the features of such processes, some of the main challenges and obstacles that those processes involve, and possible ways of dealing with them.