Failure to adjust to a new organization has major personal, team, and organizational costs. Yet, we know little about how newcomers' pre‐entry institutional assumptions influence and shape their subsequent socialization. To address this issue, we propose and test a model examining whether the discrepancy between newcomers' injunctive logics (pre‐entry beliefs about what institutional practices ought to be) and their descriptive logics (actual experience of these institutional practices) influences the development of organizational identification, perceived organizational trustworthiness, and self‐efficacy. We examined the impact of discrepant logics in a healthcare context by surveying new staff on their first day of employment and then again six weeks later (N = 264). We found that when there was a negative discrepancy between injunctive and descriptive logics (that is, when the prevailing logics did not match what newcomers thought they ought to be), organizational identification and perceived organizational trustworthiness decreased over time and consequently so did self‐efficacy. The results highlight the important role of institutional logics in shaping socialization processes and outcomes soon after organizational entry. We conclude that histories and personal and professional moral codes provide a background against which newcomers evaluate their new institutional, social, and work context. Copyright © 2016 John Wiley & Sons, Ltd.