Background: More than ever before, school principals are dealing with stress and burnout, resulting from increasing role demands and decreasing decision latitude and autonomy. Following the DemandSupport-Constraints model, reasons for stress and burnout can be found in the lack of social support in the environment. Purpose: This longitudinal study investigates whether changes in social support from colleagues, supervisors and/or the broader community affect levels of principal stress and burnout. Sample: Approximately 26% of Australia's school principals took part (N = 3572): primary (n = 2660) and secondary (n = 912) spread across all Australian states and territories. Age ranged between 46 and 55 years, and mean leadership experience was 12 years. Design and methods: Since stress and burnout are psychological phenomena that develop over time, a longitudinal approach was adopted. Data were collected across four waves, spread over four years, from 2011 to 2014.