Land managers use a variety of labor sources to implement ecological restoration projects. Reasons why these land managers decide to use or not use volunteer labor are not well known; yet, this decision can significantly shape ensuing social, psychological, and ecological benefits. To better understand how land managers' opinions influence their intentions toward using volunteers, we surveyed ecological restoration project decision makers (n = 176) from three U.S. land management agencies (the Bureau of Land Management, National Park Service, and U.S. Forest Service) in Colorado, Idaho, Utah, and Wyoming using stratified random cluster sampling. Employing the Theory of Planned Behavior, we measured factors that likely influence intention to use volunteers, including land managers' attitudes, norms, and perceived behavioral control (PBC). We used multiple regression analysis to understand the relationships among constructs, which indicated PBC was the strongest predictor of intention. Based upon intention to use volunteers, an analysis of variance (ANOVA) showed differences among land managers in terms of (1) their opinions about building community support and accomplishing more work, (2) the influence of supervisors, coworkers, and environmental groups, and (3) their perceived barriers due to a lack of trained volunteers and a lack of tasks safe for volunteers. Our results suggest environmental stewardship organizations and others that want to increase the use of ecological restoration volunteers should find ways to alleviate employees' perceived barriers, encourage supervisors to advocate for using volunteers, and when possible provide tangible information demonstrating how using volunteers can generate community support for a restoration project.