Although social support is typically associated with a number of health benefits, for some individuals support worsens outcomes, likely because receiving support can undermine feelings of competence. Some have argued that invisible support (i.e., support that recipients do not recognize as help) can reduce negative support-related health consequences (Bolger, Zuckerman, & Kessler, 2000); still, the physiological benefits of invisible support have yet to be established and likely differ as a function of self-efficacy. The purpose of this study was to investigate how visibility of support and self-efficacy interact to affect the cortisol reactivity of a support recipient. In a 2 (self-efficacy: high vs. low) x 2 (support visibility: visible vs. invisible) between-subjects, experimental design, 74 undergraduate students were primed for either high or low self-efficacy using false feedback. Participants then received either visible or invisible support from a confederate while preparing a speech as part of the Trier Social Stress Task (Kirschbaum, Pirke, & Hellhammer, 1993). A series of repeated measures analyses of variance revealed that individuals primed to have high self-efficacy experienced cortisol increases in response to the speech task when they received visible support but not invisible support. By contrast, individuals primed to have low self-efficacy experienced increased cortisol when they received invisible support but not visible support. This research suggests that although invisible support can effectively buffer stress, it is not always the best support strategy.