Avoidance job crafting refers to employees proactively changing work boundaries by reducing tasks and/or interactions with others. Although avoidance job crafting may help employees to address work demands, if noticed by others, specifically supervisors, it may trigger negative reactions from them. While previous research posits that job crafting is largely unnoticed by supervisors, using a dyadic supervisor‐employee study ( N = 141 dyads), we found that supervisors were in fact aware of their employees’ avoidance job crafting, which related to a reduction in supervisor support. This relationship was moderated by employee political skill (but not approach job crafting), such that high avoidance job crafting in combination with high political skill resulted in fewer negative outcomes, presumably because supervisors were less likely to notice their employees’ avoidance job crafting. In a second, vignette study ( N =  92 supervisors), we experimentally replicated the relation between observed avoidance job crafting and negative supervisor reactions, and found that this relation can be explained by supervisors perceiving avoidance job crafting as destructive work behavior. Our findings introduce the supervisor perspective to the job crafting literature and highlight the importance of engaging in avoidance job crafting in a skillful way that aligns with the external context.