For the past few decades, ozone (O3) in stratosphere as well as in troposphere has been identified as a global environmental concern. Stratospheric O3 depletion by human-induced emissions of CFCs (chlorofluorocarbons), HCFCs, and halons leads to an enhancement in ultraviolet-B (UV-B) radiation on Earth’s surface. These two abiotic stresses (UV-B and O3) negatively impact the biochemistry and physiology of the plants. Besides individual, the collective UV-B and O3 exposure induces oxidative stress in crops. The harmful UV radiation promotes the overproduction of ROS causing oxidative stress, degradation of photosynthetic pigments, and simultaneously affecting the working of photosynthetic efficiency and photosynthetic machinery. Researches have revealed the reduction in biomass and yield under O3 stress in plants. Moreover, similar responses have been observed under O3 stress too. In plants, the UV-B and O3, in combination, results in impaired plant growth, decline in biomass, reduction in gas exchange parameters, photosynthetic efficiency and stomatal conductance as well as reductions in yield and also alterations in nutritional quality of the produce. This chapter addresses the individual as well as the combined effects of UV-B and O3 on biomass, physiology, yield, and seed quality chiefly on crop plants. Both stresses can individually exert negative impacts on plants and are generally milder compared to elevated levels of O3, and their combined effect is synergistic that can further exacerbate these negative impacts. Nevertheless, the mode of interaction of UV-B and O3 can also be less than additive and the response can be more damaging under individual exposure of O3.