Tanzanian teachers have been criticised for a variety of behaviours such as absenteeism, lack of preparation and rote-teaching. This paper introduces an analytical framework that attempts to provide explanations for these behaviours by locating Capability Approach concepts within a Critical Realist theory of causation. Qualitative data from three primary schools will contextualise this framework and demonstrate how criticised practices are often a product of teachers contending with capability constraint. By reframing teacher actions this way it is hoped that a more nuanced understanding of teacher performance might be had, which may enhance measures aiming to improve it. (Contains 3 figures.)