Sperm morphology can predict the reproductive male fertilizing potential. This study aimed to determine the morphological and morphometric spermatozoa characteristics from guinea pigs subjected to different photoperiodic stimulation. Thirty F1 guinea pigs were randomly assigned to three photoperiodic treatments: FT1 (photoperiod with 10L/14D LED light), FT2 (photoperiod with 10L/14D sunlight), and FT0 (room without direct light source). At 107 ± 9.8 days of age, sperm concentration and motility were higher in FT0 and FT1 (p<0.05); furthermore, there were no differences in nucleus length and ellipticity between FT0 and FT1, but FT1 was higher in perimeter and nuclear area, while FT0 was higher in roughness, regularity, midpiece length and tail (p<0.01). Expanding acrosome (Type 2) was more frequent in FT2, but there was variation in head measurements between all morphological categories. Pregnancy rate, calving age and mating age were higher in FT0, meanwhile FT1 initiated successful matings earlier (p<0.01). FT0 had a higher fertility rate, and FT1 age of mating and first calving were earlier than FT0 but no pregnancies were reported for FT2. The photoperiodic stimulation can increase the morphometric dimensions of guinea pig spermatozoa, favoring the reproductive characteristics, but sunlight could reduce their size due to heat stress.