This study was carried out with the aim of determining the effects of wheatgrass lengths on antioxidant activity and total phenolic content of wheatgrass belonging to different cultivars (Triticum spp.) in laboratory conditions in 2017. When the wheat seedlings grown in plastic containers under soilless conditions reached three levels of wheatgrass length (5-6, 8-9, and 11-12 cm), the seedlings were cut from the root collar and dried in an oven. As a result of analysis of the dried material, it was found that the cut lengths of wheatgrass significantly (P < 0.01) affected antioxidant activity and total phenolic content of wheatgrass. Ten wheat cultivars belonging to Triticum monococcum L., T. durum L., and T. aestivum L. were used. Wheatgrass was cut at three lengths (5-6, 8-9, and 11-12 cm). It was found that the wheatgrass lengths had a significant (P < 0.01) effect on antioxidant and total phenolic content of wheatgrass. In addition, in terms of these traits, the most suitable wheatgrass length for cutting changed depending on the wheat species and also cultivars. The highest (P < 0.01) antioxidant activity and total phenolic content (TPC) were also determined at three wheatgrass lengths in cultivar Saribasak. The average values obtained from Saribasak wheatgrass were 31.0% for DPPH-free radical scavenging activity and 51.6 mg GAE(-1) dry weight for TPC. The results of the analysis suggested that Sanbasak is the most promising cultivar in terms of both antioxidant activity and TPC in wheatgrass.