Selenium (Se) is an essential element for mammals but a physiological requirement for Se has not been shown for higher plants. Lower plants, such as algae, require Se for normal growth and development, and contain a Se-dependent antioxidant enzyme. Lentil (Lens culinaris Medik), a nutritious traditional pulse crop, has been experiencing a declining area of production around the world, due to lower yields, and marginal soils. We conducted several preliminary field and greenhouse studies to determine whether selenium (Se) fertilization can increase lentil yield, seed quality (both seed Se concentration and speciation), and antioxidant activity. Selenium was provided to several lentil accessions and cultivars as selenate or selenite by foliar or soil application and the resulting lentil biomass, grain yield, seed Se concentration, and Se speciation was determined. Seed Se concentration was measured using inductively coupled plasma optical emission spectrometry (ICP-OES) after acid digestion. Seed Se speciation was measured using High Performance Liquid Chromatography ICP-mass spectrometry (LC-ICP-MS) system. Application of Se significantly increased lentil biomass (10-30%), grain yield (10-20%), and seed Se concentrations (3-folds) compared to the control. Both application methods and both Se forms increased concentrations of organic Se forms (selenocysteine and selenomethionine) in lentil seeds. Application of selenite significantly increased the antioxidant activity (66% inhibition) of lentils compared to the selenite (64% inhibition) and control (59% inhibition). Our data clearly show that Se application increased the Se uptake by the plant, resulting in higher grain yield, biomass, and concentration of Se in the seeds. Thus, it appears that Se biofortification by Se-fertilization could not only improve lentil seed Se nutrient quality but also grain yields providing new whole-food opportunities to deliver Se to Se-deficient populations.