The purpose of this study was to investigate seed germination of Leandra breviflora, Tibouchina benthamiana, Tibouchina grandifolia and Tibouchina moricandiana under different light and temperature conditions, by assessing germination percentage and speed. The optimum temperature for seed germination of all species was 30°C; reduction or absence of germination took place at 15 and 35°C. All species studied are fotoblastic positive for all temperatures tested; 24 hours photoperiod caused a reduction in germination percentage and speed, which suggests that the seeds of the species studied have a photoperiodic behaviour of short days.