Competition influences the expression of morphological, physiological, and behavioral traits and also regulates ecological and evolutionary dynamics. This study aims to identify and characterize changes in wing morphology in response to intra- and interspecific competition in three necrophagous blowfly species. Using geometric morphometry, we analyzed 3,238 wings from Lucilia sericata (Meigen, 1826), Calliphora vicina Robineau-Desvoidy, 1830, and C. vomitoria (Linnaeus, 1758) raised under cloistered and pairwise conditions. The three species reacted similarly to intraspecific competition—reducing wing size with increased competition—but displayed contrasting patterns of response to interspecific competition. Lucilia sericata displayed a directional change in wing shape in response to an interspecific competitor, while C. vicina increased the scattering of individuals across the morphospace, and C. vomitoria displayed no significant change in response to the same stimulus. Our results show that the same stimulus yields distinctive responses; thus, different competition-related strategies are expected to occur in the three species.