Long used as a source of food, beverages, and fiber, Agave exhibits potential to be cultivated as a crop to produce alternative sweeteners, bioenergy, and a variety of other end uses. However, little is known regarding the productivity levels of Agave when grown in saline soils in semiarid regions. Hydroponic experiments were carried out to evaluate the effects of salinity on biomass accumulation and nutrient levels of young plants of Agave parryi, Agave utahensis ssp. kaibabensis, Agave utahensis ssp. utahensis, and Agave weberi. Salinity treatments (0.6, 3.0, 6.0, and 9.0 dS·m−1) were imposed in each experiment. Both subspecies of A. utahensis were sensitive to salt treatments. In the higher salinity treatments, A. utahensis ssp. utahensis exhibited high mortality; both subspecies had lower plant dry weights. Agave parryi was more tolerant, but experienced a decrease in plant dry weight in the 9.0 dS·m−1 treatment. The biomass of A. weberi was unaffected by any level of salinity. Calcium, Mg, S, and Mn levels decreased in both A. parryi and A. weberi at higher salinity levels. Potassium and P levels in A. parryi decreased in the higher salt treatments. Decreases in nutrients were not severe enough to cause any apparent nutrient deficiencies in A. parryi and A. weberi. Agave parryi and A. weberi tolerated salinity at higher levels than expected, and may show promise for cultivation in saline soils.