Although judges may be well intended when taking an oath to be impartial when they reach the bench, psychological and legal literature suggests that their legal approaches, behaviour, and decision‐making processes are subconsciously impacted by biases stemming from and influenced by their attitudes, ideology, backgrounds, and previous experiences. Drawing from prior models of sources of bias in legal contexts and existing literature on judges, this paper discusses and models potential sources of pro‐prosecution bias in judges with prosecutorial backgrounds. These include (1) professional and self‐selection into the judiciary; (2) prosecutorial socialization and attitudes that can shape a prosecutorial mindset; and (3) the effects of common unconscious biases, confirmation bias and role induced bias, that may shape judicial behaviour through formed beliefs and approaches stemming from the prosecutorial mindset and selection into the judiciary. As the vast majority of judges are former prosecutors in the U.S. as well as in many other countries, this paper considers possible ways to deal with pro‐prosecution bias and the potential importance of diversifying judges' professional backgrounds.