The main objectives of this study was to estimate combining ability and heterotic groups for 16 white maize inbred lines using line × tester mating design.Thirty-two whitethree-way crosses resulting fromcrosses between 16 inbred lines with two testers(SC 131 and SC Gm 1)and the check TWC  321  were evaluated at three Research Stations; Gemmeiza, Sakha and Mallawyin 2020 season.Mean square analysis cleared the variability among lines and testers and their interaction for most studied traits. The non-additive gene effects were more important than additive ones in the inheritance of days to 50% silking and grain yield, while the additive ones were the predominant for ear height and plant height. The best inbred lines for general combining effects were Gm5, Gm 6 and Gm 7 for days to silking (earliness),plant height (shortness) and ear height(lower ear position),and Gm 12,Gm 13 and Gm 14 for grain yield. The two crosses; Gm 14 x SC131 and Gm 14 x SC Gm 1 were significantly out-yielded compared with the check TWC 321 (31.3 ard./fed), therefore they will be taken in the next stage for more accurate evaluation in the national program of maize. Sixteen inbred lines were classified into the following two heterotic groups using HSGCA for grain yield group-1 (tester SC131) included inbred lines Gm 2, Gm 5, Gm 6, Gm7,Gm8, Gm13 and Gm 16while group-2 (tester SC Gm1) included inbred lines Gm1,Gm9, Gm 11 and Gm 15. These groups could be used in breeding programs for selecting the best parents in making hybrids