Nudges are simple and effective means to help people make decisions that could benefit themselves or society. However, effects of nudges are limited to local maxima, as they are almost always designed with the “average” person in mind, instead of being customized to different individuals. Such “nudge personalization” has been advocated before, but its actual potency and feasibility has never been systematically investigated. Using the ubiquitous domain of online password nudges as our testbed, we present a novel approach that utilizes people’s decision-making style to personalize the online nudge they receive. In two large-scale studies, we show how and when personalized nudges can lead to considerably stronger and more secure passwords, compared to administering “one-size-fits-all” nudges. We discuss the implications of this findings and how more efforts by researchers and policy-makers should and could be made to guarantee that each individual is nudged in a way most right for them.