Using a farm household data from 3 agroecological zones of Ghana, this paper investigates the causal relationship between the adoption of improved maize variety and technical efficiency or productivity. The empirical results show a positive relationship between the adoption of improved maize variety and technical efficiency or productivity of farmers in the Semi-deciduous forest and Guinea Savannah zones. Generally, adopters of improved maize variety are about 6% to 8% more efficient than non-adopters. The estimated percentage increase in productivity due to the adoption of improved maize variety is about 53%. In the Semi-deciduous forest agroecological zone, adopters of improved maize variety are about 25% to 36% more efficient than non-adopters whilst in the Guinea Savannah agroecological zone, adopters of improved maize variety are about 15% to 26% more efficient than non-adopters. The estimated percentage increase in productivity due to adoption of the improved maize variety is about 8% in the Semi-deciduous forest zone and about 11% in the Guinea Savannah zone. The impact of adoption on technical efficiency in the Transitional zone is however negative. Adopters of improved maize variety are 7% to 8% less efficient than non-adopters and the estimated percentage decrease in productivity due to adoption of the improved maize variety is about 15%. Food safety net policies should pay attention to increased development and dissemination of improved crop varieties suitable to different agroecological zones.