Individuals have a drive towards maximising the efficiency of their actions – given a choice of two actions to achieve the same goal, they will choose the action that incurs the fewest costs. When performing joint actions, on the other hand, people prioritise the joint or co-efficiency of the overall action even when this comes at a cost to themselves, suggesting that participants distribute joint actions according to a rational decision-making strategy that prioritises the efficiency of the dyad over either individual. However, it remains an open question whether participants in a joint action are willing to sacrifice their partner’s individual efficiency for the greater good, when forcing a partner to incur additional costs may be interpreted as unfair. We investigate whether the reputational motivation to be seen as fair would interfere with the tendency to maximise co-efficiency. In two experiments, we explored how participants chose to distribute a motor task that required either a fair or unfair distribution of labour. Whether there was opportunity for reciprocity (Experiment 1) or not (Experiment 2), participants systematically maximised the coefficiency of their joint actions regardless of how unfair this distribution proved to be regarding individual action costs. Our results suggest that people allocate tasks within a joint action using a decision-making strategy that prioritises overall efficiency over both individual efficiency and considerations of fairness.