Although the literature provides widespread evidence for the effect of power on action, a systematic understanding of why low power individuals are less prone to action is still lacking. We focus on proactive behavior as a particular form of action and propose a relational underpinning of the link between low power and reduced proactive behavior through the framework of attachment theory. We predict that the experience of low power will increase attachment anxiety, and that this increase in attachment anxiety will reduce proactive behavior. We test the proposed theory in a series of four pre-registered experiments and one quasi-experimental field study. In Study 1, 2, and 3, we test the mediating role of attachment anxiety on the relationship between low power and proactivity. In Study 4 and 5, we test theoretically driven attachment security interventions to mitigate the link between low power and reduced proactivity. We demonstrate that attachment security interventions help low power individuals to be more proactive in an organizational field quasi-experiment (Study 4) and in an experiment (Study 5). Overall, we find support for attachment anxiety as an important factor in the experience of low power individuals which inhibits proactive behavior; we further offer a powerful intervention grounded in attachment theory to ameliorate this effect.