Prior research suggests that the organizational context supports the emergence of employee ambidexterity; however, the interplay between formal and informal context has been largely unexplored. We analyze this interplay with a multilevel, multisource data set of 2446 individual employees nested in 77 organizations. We find that a promotion climate—unlike a prevention climate—contributes to employee ambidexterity. In addition, formalization positively moderates the effects of both promotion and prevention climate on employee ambidexterity, while centralization weakens the positive effect of promotion climate. Our results advance a contingency perspective that brings together formal and informal contextual drivers of employee ambidexterity and shows that even though an informal climate signals the preferred manner of goal pursuit, a formal structure affects the impact of such signals by delineating opportunity corridors of admissible behaviors.