The objective of the present investigation was to estimate genetic variance components and type of gene action controlling yield, its components and quality characteristics of some cotton crosses, by means of the six populations (P1, P2, F1, F2, BC1 and BC2) of the four cotton crosses. Results revealed that the estimated mean effects (m) were highly significant for all traits in all crosses, indicated that these traits were quantitatively inherited. Additive and dominant gene effects were highly significant for No. of bolls/plant, boll weight in the fourth cross, 2.5% span length in the second cross, fiber fineness in the first and fourth crosses, with lager of dominance effects in magnitude than additive ones. Dominance, additivexdominance and dominancexdominance were at least significant for No. of bolls/plant in the first cross, seed and lint cotton yields in the first and second crosses, boll weight in the fourth cross, 2.5% span length and fiber fineness in the first cross and fiber strength in the second cross, indicated that these traits were greatly affected by dominance and their non-allelic interactions. Narrow-sense heritability and genetic advance were low in most cases due to the opposite directions of dominance and dominancexdominance effects resulted in lower overall dominance variance. It could be concluded that heterosis over mid and better parent were highly significant in all crosses for No. of bolls/plant, seed and lint cotton yields/plant with low inbreeding depression.