Providing safe, nutritious, and wholesome food for poor and undernourished populations has been a major challenge for the developing world. Acute shortage, unreliable supply, and elevated costs of protein-rich foods of animal origin in the developing and underdeveloped countries have resulted in the search for inexpensive and reliable alternative sources of protein of plant origin. Some of the wild and underutilized legumes (such as Canavalia, Mucuna, and Sesbania, for example) have been investigated and found to possess rich nutraceutical value. However, the greatest impediment to utilizing these legumes is the presence of antinutrients, which could be successfully removed or deactivated by employing certain processing methods (cooking, dry heat treatments, germination, irradiation, among others). This review focuses on providing the details on some of the wild and underutilized legumes that might have high potential to be used as human food and animal feed, along with providing information for overcoming the malnutrition-associated problems and also for future commercial exploitation such as a source of nutraceuticals, for new food formulations, biofortification, and in product development.