Objective The current study sought to conduct a preliminary investigation of the effectiveness and feasibility of a novel, self‐guided online self‐compassion training for reducing psychological distress and increasing self‐compassion and happiness among psychology trainees. Method A 6‐week online self‐compassion cultivation program was developed and delivered to Australian psychology trainees (n = 37), and a pre‐experimental repeated‐measures design was used to collect change data on self‐compassion, happiness, perceived stress, emotion regulation difficulties as well as symptoms of depression, anxiety, and stress. Results Participants reported significant increases in self‐compassion and happiness and significant decreases in depression, stress, and emotion regulation difficulties between pretest and posttest, with the majority of changes maintained at 3‐month follow up. Conclusion  This study provides preliminary evidence supporting the effectiveness and acceptability of online self‐compassion training as a positive, integrated, and meaningful way of reducing distress and promoting self‐compassion and happiness among trainee psychologists.