Social entrepreneurship is a hybrid form of entrepreneurship combining the aspirations to fulfil a social mission and independently generate financial income on a competitive market. While social enterprises offer notable chances to make up for inefficiencies in sustainable social value creation by governments and Non-Governmental Organizations during social hardships, they face the risk of losing their social missions over time. This effect is coined mission drift (MD). To date, MD-research suffers from notable shortcomings like the negligence of possible effects on social enterprise employees and robust experimental evidence. My study employs a sample of university students (N = 137) and a vignette-based experimental design to examine how different kinds of MD (no MD; soft MD, strong MD, mission shift from social to ecological) affect important work-related attitudes of social enterprise employees. MANOVA results yield that, compared to no MD, strong MD has a notable and broad detrimental impact. Furthermore, indications for differential effects depending on MD-magnitude and for mission shift are found. Despite acknowledgeable limitations, the current study emphasizes the importance of an employee perspective on MD and offers rare causal evidence on MD-consequences.