Maize (Zea mays L.) is the most popular highland cereal in South Asia, and hybrids are being promoted to enhance yields. Thus, a field study evaluated the growth and yields of two hybrid and two open-pollinated varieties in two major (wet) and minor (dry) seasons of Sri Lanka, when grown as a mono crop and when intercropped with mungbean [Vigna radiata (L.) Wilczek]. The growth and yields of the hybrids were greater under both mono and mixed crop conditions in the major seasons, while the performance of open-pollinated varieties was significantly superior in the minor seasons, when the crops are subjected to moisture stress due to lower rainfall. The potential of using different types of maize for smallholder cropping in South Asia in the two seasons is presented.