A half diallel set of crosses among six highly diverse barley (Hordeum vulgare L.) genotypes were evaluated at Karahta station of field crops research (GCSAR) Damascus Governorate, during 2010-2011 and 2011-2012 seasons to study heterosis and combining ability components for plant height, grain yield per plant, number of spikes per plant, number of grains per spike and thousand kernel weight.