Working while ill (presenteeism) with symptoms of influenza-like illness can contribute to outbreaks, but little is known about school nurse presenteeism. Missouri Association of School Nurses members (N = 396) were sent a survey in 2013/2014. A chi square test was conducted to compare having a school culture that encourages presenteeism versus actual sick leave policies. Multivariate logistic regression was conducted to delineate factors associated with presenteeism. In total, 133 school nurses participated (33.6% response rate). Almost half (42.1%, n = 56) reported presenteeism. Nurses were more likely to feel pressure to engage in presenteeism than reported punitive sick leave policies (14.3% vs. 3.8%, ² = 18.3, p < .001). Presenteeism was associated with perceived pressure, odds ratio (OR) = 4.8, confidence interval (CI) = [1.5, 15.8], p < .01, and having a mild illness, OR = 3.6, CI = [1.4, 9.7], p = .01. Many school nurses engage in presenteeism, and this appears to be associated with organizational cultural norms rather than established sick leave policies.