Abstract: Evaluation of ninety hybrids of bitter gourd resulting from full diallel mating of ten genetically diverse genotypes for earliness, yield and quality characters had revealed the presence of heterotic vigour. Fifty nine hybrid combinations were found to exhibit negative significant heterobeltiosis for days to first female flower appearance and the hybrid CO-1 x GL had registered favourable values for this trait. The hybrid CO-1 x MC-105 registered negative significant relative heterosis, heterobeltiosis and standard heterosis for node at which the first female flower appears. The heterosis for sex ratio was found to be in the desired direction in UB x GL and seventy six hybrids showed significant negative heterobeltiosis for sex ratio. The highest significant relative heterosis (KR x UB) and heterobeltiosis (MC-10 x KR) for fruit length was also observed. The highest positive and significant standard heterosis was observed in the hybrid Priyanka x GL for fruit length. The estimate of heterobeltiosis for fruit weight had shown positively significant value for fifteen hybrids, and it was the highest in KR x USL. Among the ninety hybrids, sixteen hybrids had registered positive and significant heterobeltiosis values for number of fruits per vine, and the hybrid Preethi x MC-30 had the highest value for this trait. The highest positive heterobeltiosis for yield of fruits per vine was recorded in KR x USL followed by Preethi x MC-30. However, the estimates of standard heterosis for fruit yield revealed that the hybrid Preethi x MC-30 had the highest positive significant value followed by the hybrid KR x USL. In order of merit the hybrids viz., Preethi x MC-30, KR x USL and MC-105 x MC-10 were noted to be the top performing hybrids with respect to yield and quality parameters since they had showed significant heterotic values.