["Business Ethics, the Environment &Responsibility, Volume 35, Issue 3, Page 1536-1560, July 2026. ", "\nABSTRACT\nA supportive ethical culture (EC) can encourage moral behavior among employees and help them avoid wrongdoing. One option for fostering EC is ethics training; its longer‐term effectiveness, however, has rarely been examined, especially in countries lacking strong regulatory environments. Accordingly, we used a comprehensive theory‐driven approach to train the upper echelons (18 males, 16 females) from two organizations in Colombia. In turn, they agreed to use their influence in a manner that would cascade through the hierarchy. EC perceptions of 275 staff across the companies (n1 = 193, n2 = 82; total = 275) were assessed 1–2 months and 9–10 months post‐training. Relative to pre‐training levels, both overall EC and its subdimensions significantly increased 1–2 months out, but these gains were not sustained 9–10 months later. Qualitative findings of data collected in each company (8 interviews per company) suggested that ensuring effective transfer of training from the upper echelons was a challenge.\n"]