Onion is widely cultivated as a high-value spice and vegetable for culinary and medicinal purposes, dating back to 5000 years. Mediterranean regions harbor huge diversity for its cultivated and wild forms. From there, it has been spread to the different parts of the world and has become an important vegetable in everyday diet. Therefore, its production needs to keep pace of the increasing population. In the past, open-pollinated varieties (OPVs) have dominated onion production statistics. Hybrid varieties provide an excellent alternative to achieve substantial yield improvements by exploitation of heterosis. Commercial hybrids development majorly relies on availability of stable male sterile system and suitable inbreds. A report of cytoplasmic male sterility in the early 1930s has opened immense scope for exploiting heterosis and increasing yield potential through hybrid varieties. The popularity of hybrid onion has shown steady growth and is still growing in various regions around the world. However, hybrid development in onion is posed by difficulties such as high cross-pollination and inbreeding depression. Nevertheless, hybrids have outperformed OP varieties in several cases. Currently, many developed countries have shifted to hybrid onion cultivation, but developing countries are still moving in that direction. Therefore, global onion seed market is expanding. Seed production with quality control standards to provide legal framework for developed hybrids is the need of the hour.