This investigation was conducted at Shandaweel Research Station in the seasons 2019, 2020 and 2021, to estimate some genetic parameters for grain yield and some yield related traits, using the six populations, i.e. P1, P2, F1, F2, BC1 and BC2 of two grain sorghum crosses viz. RSh-13 × RSh-37 (Cross I) and RSh-18 × RSh-14 (Cross II). Besides P1, P2 and F1 were evaluated for drought tolerance under three levels of water deficit [100, 60 and 40% ET] in three separate experiments. In addition, F2, BC1 and BC2 were also evaluated under drought conditions [60 and 40% ET] in separate experiments. Results of analysis of variance indicated significant differences among the studied generations of each cross for studied traits. The genetic variances within F2 population were also found to be significant for all the studied traits in the two crosses, therefore genetic parameters for additive, dominance and epistasis were estimated. The scaling test values A, B, C and D were significant for different studied traits, suggesting the presence of non-allelic interaction. The positive and significant estimates for various types of gene action revealed that the dominance × dominance type of epistatic gene action, which accounted for 17 cases out of a total of 24 cases (70.8%), followed by the additive gene effect (45%) contributed by a large portion of the genetic components controlling the inheritance of the studied traits. Estimates of broad-sense heritability were high (>80%) for all the studied traits under 60 and 40% ET. In the same regard, under both conditions, the values of heritability in the narrow sense ranged from low to moderate in all investigated traits. The expected genetic advance as percentage of the F2 mean (Δg%) values were high enough to select for improving the studied traits in the segregating generations.