This research aimed to determine the effects of different zinc (Zn) levels on the grain yield and some phenological characteristics of the Fırat-87 red lentil variety (Lens culinaris Medic.). The study was conducted during the winter months of 2013-2014 and 2014- 2015 in Zn-deficit areas of Şanlıurfa, Turkey. The experimental design was a randomized complete block design with 4 replicates. The Fırat-87 lentil variety and Zn sulfate (ZnSO4.7H2O) were used as the plant material and Zn source, respectively. The Zn levels used were the control (0 kg ha-1 Zn), 5 kg ha-1 Zn, 10 kg ha-1 Zn, 15 kg ha-1 Zn, 20 kg ha-1 Zn, and 25 kg ha-1 Zn. The Zn levels were significant (P ≤ 0.01) for the harvest index, 1000-kernel weight, protein rate, and grain yield. All of the tested characteristics were positively affected by increasing applications of Zn. The grain, leaf, and soil Zn contents were higher with increasing levels of Zn. Although the highest grain yield was 15 kg ha-1 Zn in both years, according to the regression analysis, the optimum Zn level was 17 kg ha-1 Zn. However, the economic Zn level was determined as 15 kg ha-1 Zn.