Apicomplexan parasites are an ancient group of protozoan parasites that includes several significant pathogens of humans and animals. To target and invade host cells they use a unique form of actin-based motility, called gliding motility. At the centre of the molecular motor that underlies this unique mode of locomotion are short, highly dynamic actin filaments. Recent molecular work, along with the availability of completed genomes for several Apicomplexa, has highlighted unique features of parasite actin and its regulation - features that might provide new ways to block motility and, consequently, prevent infection and disease.