Heat stress due to the global warming is one of the major constraints in the way of higher wheat productivity. This field study was conducted to evaluate the effect of late sowing on the wheat yield, chlorophyll content and proline accumulation in leaves. The result indicated that the Eight wheat varieties (K-7903, HUW-234,UP-2425,RAJ-3765,K-9644,PBW-373,K-9423,K-65) were treated with the heat stress condition. Heat stress were given to wheat varieties by delay sowing of 20 and 40 days from the normal date of sowing(25 november) so that the reproductive stage of first set(T1) and vegetative as well as reproductive stage of second set (T2) could experience heat stress. Analysis of the data showed that under heat stress condition Raj-3765 and K-7903 was minimum reduction in plant height, wheat yield, spike length and no. of grain per spike than the other wheat cultivars. While the chlorophyll content of normal sowing is greater than the late sowing treatment. The maximum chlorophyll content in treatment 1 and treatment 2 under heat stress condition was recorded in Raj3765 while lowest chlorophyll content was recorded in K-9644. Proline was significantly high in susceptible varieties K-9644,K-9423 and UP-2425 whereas, tolerant variety Raj-3765 and K-7903 show the low proline content. From this study it could be concluded that the Morphological, physiological and Biochemical changes in wheat cultivars through the late sowing condition and from this experiment also conclude that the Raj-3765 is heat tolerance variety.