Total Worker Health® (TWH) is defined as policies, programs, and practices that integrate protection from work-related safety and health hazards with promotion of injury and illness prevention efforts to advance worker well-being (NIOSH 2017b). Because it is relatively new, TWH is still at an early stage of being defined and conceptualized (Hymel et al. 2011; Schill and Chosewood 2013; Sorensen et al. 2013). Indeed, recent reviews highlight gaps in TWH research. Overall, both Anger et al. (2015) and Feltner et al. (2016) noted a paucity of high quality intervention research and inconsistent acknowledgment and application of theoretical frameworks. Most of the TWH intervention studies identified in their reviews focused on single interventions designed for single, large companies and for a single category of workers. Few examples of small business TWH interventions studies exist (Healthier Workforce Center of the Midwest 2017; Sorensen et al. 2005, 2016). Thus, there is a need to consider how TWH applies and is operationalized in small businesses. The purpose of this paper is two-fold. First, we discuss the importance of studying small businesses in TWH research and practice. Second, we describe an example of a small business TWH intervention and evaluation strategy, the Small+Safe+Well (SSWell) study. Our goal is to provide a strong conceptual foundation for future research on TWH intervention efficacy, implementation, and maintenance, specific to implementing and measuring TWH in small businesses. Why Small Business? Nearly half of Americans are employed by small businesses, and future projections suggest that the number of those employed by small business will rise. In 2014, 57.9 million US workers, representing 48% of the workforce, were employed by small businesses, defined by the US Small Business Administration as <500 employees, with the vast majority (89%) of the firms having fewer than 20 employees (United States Census Bureau 2016). Future estimates indicate that there is a trend for new small businesses to start small and stay small due to the changing nature of work (Choi and Spletzer 2012). Choi and Spletzer hypothesize that this trend is due to greater emphasis on technology rather than labor modes of production. Workers in small businesses bear a disproportionate burden of occupational fatalities, illnesses, and injuries. Across all private industries in 2015, the average total recordable injury and illness incidence rate was higher among businesses with 50–۲۴۹ employees (3.7 per 100 employees) than among businesses with 1000+ employees (3.3 per 100 employees). The rate was even higher for 50–۲۴۹ employee sized businesses in specific industries, such as manufacturing (4.5 per 100) and nursing and residential care (7.2 per 100) (Bureau of Labor Statistics 2015). It is likely that these data underestimate the burden of occupational injury and illness among small businesses due to issues such as underreporting and difficulty of maintaining accurate records (Dong et al. 2011).