This chapter shows how altered mitochondrial biochemistry in stress‐treated plants leads to changes in mitochondrial composition, enabling mitochondria to play a dissipative role that enhances cell survival. It then reviews how plant respiration is affected by three major environmental stresses: temperature, drought and salinity. When external stresses including chemical, abiotic, biotic and environmental stresses are applied to whole plants, a well‐known consequence is the induction of oxidative stress within plant cells. Mitochondrial metabolism is highly connected to many functions in plants and therefore tolerance to plant cell stress is a partnership between diverse cellular processes and the products of mitochondrial reactions. The chapter examines the three most analysed aspects of this partnership including, the role of mitochondria during photosynthesis, their contribution to root function and the products of mitochondria that directly fuel tolerance mechanisms.