Diabetes mellitus poses a significant public health challenge, particularly in low- and middle-income countries, which are home to over three-quarters of those affected. Prediabetes greatly increases the risk of developing diabetes, yet data on its prevalence and associated factors in East Africa are inconsistent and limited. This study conducted a systematic review of observational, community-based studies from 2013 to 2022, aiming to estimate the prevalence of prediabetes and its associated risk factors within the adult East African population. Twenty-one studies were analysed, revealing an overall prediabetes prevalence of 12.58%. Urban populations exhibited a prevalence rate twice that of rural populations (20% versus 10%). Using different diagnostic criteria, the American Diabetes Association reported a higher prevalence (21.45%) than the World Health Organization (7.20%). Prediabetes was significantly associated with older age, hypertension, and being overweight/obese. These findings emphasise the urgent need for targeted prevention and control strategies focusing on individuals with these risk factors, with the aim of reducing progression to diabetes in East Africa.