Stomata mediate gas exchanges between plant and environment. To adapt to environmental conditions, plants open and close stomatal pores and even regulate the number of stomata that develop on the epidermis. Recent studies have brought to light the elements of the genetic basis underlying stomatal development. They have also revealed how these elements are controlled by environmental factors (mainly light and carbon dioxide). In this review, we discussed the molecular basis of stomatal development and physiological mechanisms regulating this process. Future prospects related to stomatal development are proposed.