Agricultural producers lose millions of dollars annually to depredation caused by ungulates. Although multiple repellents exist, most are ineffective. Tannins are a plant‐defensive compound that have an astringent taste, reduce digestibility, reduce protein availability, and toxic to rumen microbes, resulting in the reduction of feeding by large herbivores. We hypothesized that chemical application of tannins to forages would provide a nonlethal method to reduce crop depredation in areas susceptible to ungulate damage. We designed an experiment to test the effectiveness of tannins at deterring feeding by captive white‐tailed deer (Odocoileus virginianus) on soybeans and other forages in 2010–2011 at the Wildlife Research Facility at South Dakota State University in Brookings, South Dakota, USA. First, using a cafeteria trial, we monitored weekly intake rates of captive deer (n = 10) offered a selected feed treated with varying concentrations of quebracho tannins (control, 3%, 5%, 10%, and 20%). Second, we manipulated food plots (n = 3) by treating 3 separate blocks with different concentrations (0% [control], 10%, and 20%) of tannins. We monitored feeding selection relative to tannin treatments within food plots 3 times/week, during summer (May–Jul) and autumn (Aug–Sep) using scan‐sampling. During cafeteria trials, intake rate of control feed was ≥3 times greater than all other feed treated with tannins. Similarly, in manipulated food plots, application of 10% and 20% tannins resulted in a 72% and 89% reduction in probability of feeding during the summer; this pattern of selection was intensified when trials occurred in consecutive days with the same deer. Strategic application of tannins to agricultural crops in areas prone to damage may provide a natural deterrent to crop depredation by ungulates. © 2019 The Wildlife Society.