Sainfoin (Onobrychis viciifolia Scop.) is a perennial forage legume that has received renewed interest in western Canada because of its desirable forage characteristics. The objective of this review is to summarize previous studies on the agronomy, forage yield, nutritive value, seed characteristics, and diseases and pests of sainfoin. In addition, the review also focuses on the genetic diversity and registered cultivars of sainfoin and their potential use in temperate grasslands. Past studies have reported that sainfoin has a high nutritive value, and high voluntary intake and palatability to grazing animals. In western Canada, dry matter (DM) yield of sainfoin is 80%–95% that of alfalfa (Medicago sativa L.). Unlike other legumes such as alfalfa, sainfoin does not cause bloat in grazing animals due to the presence of condensed tannins. Sainfoin is suitable for monoculture or binary mixtures with either grasses or alfalfa. Genetic diversity studies revealed that sainfoin germplasm generally has high variation within populations. Genetic variation among plants provides an opportunity to develop improved cultivars with desirable characteristics. However, compared with the other forage legumes, sainfoin is still an underdeveloped forage crop with few cultivars being available in western Canada. New sainfoin cultivars with high DM yield and persistence under regional growing conditions are required.