Theories of dishonest behavior implicitly assume language independence. Here, we investigated this assumption by comparing lying by people using a foreign language versus their native tongue. Participants rolled a die and were paid according to the outcome they reported. Because the outcome was private, they could lie to inflate their profit without risk of repercussions. Participants performed the task either in their native language or in a foreign language. With native speakers of Hebrew, Korean, Spanish, and English, we discovered that, on average, people inflate their earnings less when they use a foreign language. The outcome is explained by a dual system account that suggests that self‐serving dishonesty is an automatic tendency, which is supported by a fast and intuitive system. Because using a foreign language is less intuitive and automatic, it might engage more deliberation and reduce the temptation to lie. These findings challenge theories of ethical behavior to account for the role of the language in shaping ethical behavior.

This project was supported by the Israel Science Foundation grant number 1337/11, by a grant from the University of Chicago's Wisdom Research Project and the John Templeton Foundation, a grant by the National Science Foundation #1520074 to the University of Chicago, a grant from the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation program (grant agreements: ERC‐StG‐637915), two grants by the Spanish Ministry of Economy and Competitiveness (PSI2014‐52181‐P; PSI2017‐84539‐P), a grant from the Catalan Government (SGR 2017‐268), and a grant from the European Research Council under the European Community's Seventh Framework (FP7/2007–2013 Cooperation Grant Agreement 613465‐AThEME). Joanna D. Corey was supported by a grant from the Catalan Government (FI‐DGR).