What constitutes design ability and design expertise in architecture? Which categories of design expertise can be identified amongst architecture students? And, which factors predict the levels of expertise? These questions are answered in a survey of architecture students in Nigeria. Based on the results, students were classified into novices, advanced beginners, competent and proficient design students. Also identified are five areas of design ability or competency, which include innovation, and knowledge adaptation. The level of expertise of the students predicted their abilities to produce innovative designs and adapt design knowledge. The levels of expertise were determined by students’ use of academic resources, motivation and family support, among others. These areas can be leveraged by educations to enhance development of expertise.