Abstract: It is rational to care about proximity; closer is often better. Proximity bias can be found when people overweight proximity and are willing (for example) to suffer serious welfare losses in terms of health or wealth in return for modest welfare gains as a result of proximity. In extreme cases, proximity bias leads people to stay where they are, at significant cost to their own welfare. Proximity bias is paralleled by proximity neglect, which can be found when people underweight the welfare benefits of proximity. Proximity bias can be seen as a product of present bias, though it often has additional or distinctive characteristics (including overestimation of the welfare costs of getting from one place to another). Extreme forms of proximity bias can be counted as pathological (“hodophobia”). There is clear evidence of the importance of proximity, and suggestive evidence of proximity bias, in diverse contexts, including medical care; vaccination; eviction; voting; and public assistance. Proximity bias has significant implications for policy and law. It suggests that there may be large effects from increasing (or reducing) proximity or making proximity less (or more) salient, perhaps through the use of debiasing, online alternatives, or various forms of choice architecture.