Evidence is mounting that the rise of medium-scale investor farms and associated changes in the distribution of farm sizes are occurring in many African countries. These changes in the distribution of farm sizes are creating important and wide-ranging impacts at all stages of agricultural value chains. However, these effects remain poorly understood and only examined in a small number of countries to date. A better understanding of the effects of changing farm size distributions are urgently needed to guide policies aimed at achieving agricultural commercialisation and broader economic transformation objectives. This paper provides improved evidence for policies designed to support equitable and poverty-reducing agricultural commercialisation in Nigeria.