Stress increases among the working population in Germany. Workplace stress management interventions are therefore becoming increasingly important, especially in the public sector, which has a higher structural risk for work-related stress than other organizations. Currently, face-to-face formats dominate, but promising digital offerings are being developed. The aim of this study was to investigate the effectiveness of a stress management intervention as a face-to-face and self-guided digital format, referring to the Job Demands-Resources Model. The preregistered study applied a randomized control group design in which N = 65 public service employees were assigned to face-to-face training, an online course, or waitlist control group. Participants completed online questionnaires before the intervention, shortly after the intervention, and six weeks later. Although trends for reductions in emotional exhaustion and perceived stress were evident among the intervention groups, mixed analyses of variance showed no interaction effects between the time and group on the outcomes. The main effects showed a significant decrease in stress levels regardless of the group and significant differences between intervention groups, with the online course reporting the lowest stress level. The results indicate that digital and analog stress management interventions can have desired effects within occupational health management. However, many unpredictable events (e.g., illness, vacation during the intervention) seem to influence the effectiveness in the workplace setting, and so further research is needed.