Behavioural plasticity allows animals to attune their behaviour to rapid environmental changes. Here we focus on plasticity in male mating behaviour in response to socio–sexual conditions. We discuss existing theory, generate predictions to facilitate exploration of the benefits of plastic behaviour, and identify parameters with the highest leverage on fitness. Existing data are synthesised to assess whether plasticity occurs pre- and post-copulation, to determine the direction of changes in behaviour, and to examine if plastic behaviour is fully flexible. We find that plasticity in males is widespread and not dominated by responses that occur pre- or post-copulation. Our synthesis also highlights areas that are underexplored, such as the limited data on the ultimate fitness consequences of such plastic behaviour.