There is a high prevalence of people with intellectual disability (ID) among those in police custody. Consequently, law enforcement officers (LEOs) at the frontline of the criminal justice system are commonly required to interact with people who have ID. Notwithstanding the frequency of these interactions, research indicates that police exchanges with persons with ID frequently take place against a backdrop of tenuously-resourced disability awareness training. At the time of writing, a paucity of research data exists with respect to the experiences of LEOs operating within this training vacuum at an international level. A better understanding of their experiences could meaningfully inform research, training and improve support programmes for LEO's. We systematically reviewed six databases to identify studies published up to 1st December 2019 reporting the experience of LEOs interfacing with suspects who have an ID. Following a review of 670 abstracts, 16 studies were identified from five countries involving 983 LEOs. LEOs identified 1) a need for specialised training; 2) challenges in identifying people with ID; 3) a need to improve safeguards and 4) challenges in supporting/communicating with individuals who have ID through the investigation process.