Lentil (Lens culinaris Medik. ssp. culinaris) is one of the oldest cool season food legumes. It is a highly desirable pulse crop providing protein, iron, selenium, and zinc when included in the diet. Lentil originated from L. culinaris Medik. ssp. orientalis in the Near East, although subsequent domestication and selection over several years have reduced the genetic variation in lentil cultivars. Thus, characterization and utilization of crop wild relatives and prebreeding require attention in the crop. Other than a narrow genetic base, low and unstable yield, longer maturity, poor seedling vigor, and flower drop accompanied with abiotic and biotic stresses are the bottlenecks in lentil breeding and cultivation. Conventional breeding techniques have been deployed well for improving traits which are mostly monogenic. However, the majority of economic traits, such as yield, are governed by polygenic inheritance and G × E interaction. Recent advances in plant biotechnological tools, high-throughput genotyping, and phenotyping procedures and their applications are a way forward for improvement of such complex traits. Mutation breeding is another tool that has complemented genetic improvement in this self-pollinated crop. After the success of genome sequencing in lentils, new genomic resources are being developed, which will aid lentil researchers. The parallel utilization of genetic and genomic resources in the crop will lead to the accelerated development of improved varieties. This chapter provides an overview of the importance, current status, and future opportunities of lentil genetic improvement.