<p>When synanthropic primates are abundant and negatively impact human livelihoods, primatologists are often tasked with creating management strategies to help reduce the resulting human-primate conflict. While substantial ethnoprimatological theory exists about abundant primate populations that thrive in human modified landscapes and their relationships with humans, this theory must be translated into tangible, practical use on the ground if we want to efficiently, humanely, and cost-effectively manage these adaptable primate species. This paper is the output of a collaboration between an ethnoprimatologist and an economist to create a scientifically informed, sustainable green monkey (<i>Chlorocebus sabaeus</i>) management strategy for the Federation of St. Kitts and Nevis. Based on the results of 4&#xa0;years of data collection showing the monkeys’ negative impacts to agriculture and households in the Federation, we conducted an economic cost–benefit analysis to determine the most cost-effective strategy to manage green monkeys in these areas. Our results indicate that culling and sterilizing are economically viable options in both areas. Our collaborative strategy was critical for creating a sustainable monkey management strategy that is both economically sound and incorporates the nuanced ethnographic data that is required to place this economic model into the local cultural, historical, and political context of “the monkey problem” in St. Kitts and Nevis. Our work shows that while interdisciplinary collaborations can be challenging, economics can and should be used to help primatologists make informed decisions about the management of our study species.</p>