Theory and evidence from the behavioral science literature suggest that the widespread and rising use of lingua francas in the workplace may impact the ethical decision-making of individuals who must use foreign languages at work. We test the impact of foreign language usage on individuals’ susceptibility to bribery in workplace settings using a vignette-based randomized controlled trial in a Dutch student sample. Results suggest that there is not even a small foreign language effect on workplace bribery susceptibility. We combine traditional null hypothesis significance testing with equivalence testing methods novel to the business ethics literature that can provide statistically significant evidence of bounded or null relationships between variables. These tests suggest that the foreign language effect on workplace bribery susceptibility is bounded below even small effect sizes. Post hoc analyses provide evidence suggesting fruitful further routes of experimental research into bribery.