Under soil water-deficit conditions, the production of toxic reactive oxygen species (ROS) at cellular levels adversely affects plant growth, development and ultimately final yield. Use of biochar, a soil conditioner, is considered a newly emerging tool to increase the tolerance by antioxidant defence system in plants and to conserve moisture. Therefore, a field trial on wheat crop was conducted during 2015-2016 and 2016-2017. In this field investigation, biochar application (cotton sticks @ 4 t ha-1) was compared with no application under four levels of irrigation water-regimes at critical growth stages i.e., tillering (T), booting (B), heading (H) and milking (M) were maintained as I(T+B+H+M), I(T+B+H), I(T+B) and I(T+M). The results depicted that maximum grain yield, due to significant improvement in entire yield related traits, was harvested by BC application with water-regimes at I(T+B+H+M) followed by I(T+M) during both years of trial. Soil-applied BC triggered wheat plant antioxidant defense system and improved performance of gas exchange behavior under irrigation-regimes at tillering and booting stages. Overall results indicated that biochar application is effective under limited water conditions. In conclusion, biochar application with only two irrigations at tillering and booting stages of wheat seemed a viable technique to get better yield and water productivity of wheat particularly under water limited conditions.