Environmental stressors are ubiquitous and can impact disease susceptibility and transmission in complex ways. Stress can alter an individual's phenotype through effects on reproduction, growth, and development, as well as their stress response and immune function. This in turn can influence their susceptibility to disease and ability to transmit disease to others. The timing, duration, and intensity of stress exposure are important factors that may increase or decrease disease risk in complex, nonlinear ways. Research is needed to better understand how stressors like pollution contribute to disease emergence and outbreaks through their effects beyond just susceptibility, and how individual stress profiles impact transmission capacity and recovery from disease.