Auxins are unique among plant signalling molecules in that they are subject to polar transport. Plants employ specialized influx and efflux carrier proteins to transport the auxin indole-3-acetic acid (IAA) in and out of cells. Until recently, auxin transport research has largely focused on the role of the efflux carrier. Given our rapidly advancing knowledge about the development importance of auxin uptake, this review aims to redress the balance by exclusively focusing on the auxin influx carrier. We will review the discovery, molecular characterization, evolution and developmental function(s) of the auxin influx carrier.