With fascinating photophysical properties and a strong potential to utilize solar energy, metal halide perovskites (MHPs) have become a prominent feature within photocatalysis research. However, the effectiveness of single MHP photocatalysts is relatively poor. The introduction of a second component to form a heterojunction represents a well‐established route to accelerate carrier migration and boost reaction rates, thus increasing the photoactivity. Recently, there have been several scientific advances related to the design of MHP‐based heterojunction photocatalysts, including Schottky, type II, and Z‐scheme heterojunctions. In this Review, we systematically discuss and critically appraise recent developments in MHP‐based heterojunction photocatalysis. In addition, the techniques for identifying the type of active heterojunctions are evaluated and we conclude by briefly outlining the ongoing challenges and future directions for promising photocatalysts based on MHP heterojunctions.