Background and Objectives: Chronic stress contributes to psychopathology and the practise of yoga is suggested to decrease stress and improve well-being. However, the literature often reports methodological problems (cross-sectional designs, sample sizes ≤ 20, and limited exploration of community populations). The aim of this study was to address these limitations and evaluate the potential psychological benefits of yoga to a non-clinical population. Methods: Women (N = 116) reporting chronic stress participated in this longitudinal study. Participants were allocated to a twice-weekly, hour-long yoga class for a period of two months, or a waitlist-control. Indicators of psychological well-being were measured at baseline, post-test and one-month follow-up. Results: Psychological distress decreased over time in both groups, however the control group experienced decreases in positive effect compared with the yoga group. Curvilinear trends were observed, indicating that trajectories of improvement seen at post-test were not robustly seen at follow-up. Conclusion: The study indicates that short-term yoga practise may yield some benefits to stressed individuals, but that evaluation over a longer term of practise may be required to determine the optimal dose for improvements and maintenance. Differential treatment effects may be difficult to detect in studies with populations that may already be motivated to improve their health.