The effect of drought on crops is very significant and will affect world food supply due to climate change. Gene action, general combining ability (GCA) and specific (SCA) combining ability of 66 single cross hybrids of extra early maize derived using the diallel mating design involving 12 parents were evaluated under drought conditions. The design of the experiment was a 10 × 7 randomised incomplete block design with two replications. The mean squares of GCA were larger than those of SCA for the observed traits except for grain yield. The relative importance of GCA over SCA was observed to be close to unity for some of the observed traits. The correlation between yield and plant aspect, anthesis silking interval, ear aspect and stay green characteristics (SG) was negative and significant. Selection for genotype with low values in these traits will lead to indirect selection for high yielding genotypes. The inbred TZdEEI 11 and a hybrid, TZdEEI 1 × TZEEI 58, which had highly significant positive GCAs for grain yield and negative GCAs for SG, were identified as a good inbred line tester and single cross tester, respectively. From the study, the inheritance of genes was an additive effect, therefore, the prediction of performance of hybrids for the traits observed under drought conditions can be done using only GCA except for grain yield.