An experiment was conducted on five parental lines and their 10 cross combinations of bitter gourd obtained from half diallel to investigate gene action, combining ability and extent of heterosis for yield and yield contributing traits during kharif, 2012 and rabi, 2012-13 at Vegetable Research Station, Rajendranagar, Hyderabad. Variances due to SCA were higher than corresponding GCA variances for all the characters except for node of first pistillate flower appearance and number of fruits per vine indicating the preponderance of non-additive gene action involved in the inheritance of these traits. Out of the five parents, RNMC-55 and RNMC-52 as good general combiners for yield and yield attributes. RNMC-51 X RNMC-53 is best cross combination for days to first fruit harvest, days to last fruit harvest, fruit yield, number of primary branches and vine length, RNMC-53 X RNMC-55 was the best specific combiner for average fruit weight and fruit flesh thickness and the cross combination RNMC-54 X RNMC-55 recorded highest significant sca effects for node of first pistillate flower appearance, fruit diameter and number of fruits per vine and the hybrid RNMC-52 X RNMC-54 was the best specific combiner for fruit length. The cross combinations RNMC-53 X RNMC-55 (31.19%) and RNMC-52 X RNMC-55 (25.90%) exhibited high standard heterosis for fruit yield per vine in addition to significant specific combining ability, can be further tested in large scale yield trails before recommending for commercial cultivation.