Academic selection for post-primary education is an important feature of the educational landscape in some parts of the United Kingdom, most notably in Northern Ireland and some areas of England, in addition to several other global contexts. This work systematically reviewed studies in a UK context which investigated the consequences of academic selection. The United Kingdom provided a suitable context for the review because both academic selection and all-ability post-primary education in comprehensive schools have featured, and continue to feature, in its education system, thus permitting a comparison of the relative merits of the two systems. Thirty-two publications met the inclusion criteria and were included in the narrative review. Results of the review indicate that, when relevant student and school characteristics are controlled for, academic selection has a negligible overall effect on academic achievement relative to all-ability comprehensive post-primary education. The findings also indicate that there is negligible difference between the capacity of the two systems to promote intergenerational social mobility, but that academic selection potentially reinforces and further entrenches socioeconomic disparities in educational outcomes. Possible gaps in the evidence base are highlighted and implications for further research, policy and practice are elucidated.