The objective was to evaluate the response of lettuce seedlings to foliar application of different sources and doses of zinc. The experiment was carried out in a greenhouse, and the design was completely randomized in a factorial scheme (3 x 5), consisting of 3 sources with 5 doses each: Zn sulfate (0, 50, 100, 150 and 200 g Zn ha-1), Zn oxide (0, 187, 375, 562 and 750 g Zn ha-1) and Zn chelate (0; 36.25; 72,50; 108,40; and 145 g Zn ha-1), with 4 repetitions. The highest levels of foliar Zn were obtained at doses of 200, 562 and 72,50 g Zn ha-1, from sulfate, oxide and chelate sources, respectively.