This study was carried out during the two successive seasons 2014/2015 and 2015/2016 at the experimental farm of Sakha Agricultural Research Station, Kafr El-Sheikh, Egypt. Eight bread wheat (Triticum aestivum L.) cultivars and lines, differing in their earliness were used as parents and evaluated with their 28 F1's under optimum (29^th Nov.) and late (29^th Dec) sowing dates. The studied characters were earliness, grain yield and its components. significant differences were detected between the two sowing dates and among the studied genotypes in each sowing date and across the two sowing dates. The mean squares of GCA and SCA for most studied characters were significant or heighly significant under both sowing dates. Means of the parents and their crosses were decreased under late sowing date for all the studied characters. The early parents and most of their F1's had the desirable mean values for combining ability and heterosis effects for earliness characters. Moreover, the parents Giza 171, Misr 2 and Line 1 (late parents) were the best parents for mean performance and general combining ability (GCA) for grain yield and its components in most cases. Four crosses resulting from late and early parents under both sowing dates were the highest ones and could be used in advanced studies for earliness and grain yield potential. The GCA/SCA ratios were more than unity for most studied characters under both sowing dates.