In order to study how the environment can influence the relationship between the stellar mass and effective radius for nearby galaxies (z < 0.12), we use a mass-complete sample extracted from the NYU-Value Added Galaxy Catalogue. This sample contains almost 232 000 objects with masses of up to 3 × 1011 M⊙. For every galaxy in our sample, we explore the surrounding density within 2 Mpc using two distinct estimators of the environment. We find that galaxies are slightly larger in the field than in high-density regions. This effect is more pronounced for late-type morphologies (˜7.5 per cent larger) and especially at low masses (M* < 2 × 1010 M⊙), although it is also measurable in early-type galaxies (˜3.5 per cent larger). The environment also leaves a subtle imprint in the scatter of the stellar mass-size relation. This scatter is larger in low-density regions than in high-density regions for both morphologies, on average ˜3.5 per cent larger for early-type and ˜0.8 per cent for late-type galaxies. Late-type galaxies with low masses (M* < 2 × 1010 M⊙) show the largest differences in the scatter among environments. The scatter is ˜20 per cent larger in the field than in clusters for these low-mass objects. Our analysis suggests that galaxies in clusters form earlier than those in the field. In addition, cluster galaxies seem to originate from a more homogeneous family of progenitors.