Construction workforces’ health behaviors have received little attention compared with work injury risks and management. Formulated caffeinated beverage (FCB) (energy drink) consumption is relatively new to construction sites and excessive consumption may have effects on both health and safety owing to known short- and long-term physiological responses. This study contributes to understanding drivers and deterrents of caffeine and FCB consumption in construction. Data were collected from workers at six construction sites in Queensland, Australia, using mixed-method research design involving semistructured interviews (70) and quantitative surveys (n=250). Convergent interviewing underpinned by the theory of reasoned action was used to analyze qualitative interviews. Bivariate logistic regression analyses were conducted to examine determinants of caffeine and FCB consumption. Work hours were associated with caffeine consumption >210  mg/day (β=−0.046, p=0.037). Qualitative results indicate energy drinks are consumed widely and regularly on site, with stress and attempts to manage the pace, timing, and intensity seen as drivers for consumption. In combination, these findings suggest management of FCBs on construction sites requires more attention as a potential health hazard.