School nurses often play large roles in implementation of school vaccination requirements aimed at controlling the spread of communicable disease. We analyzed the association between the presence of a school nurse and school-level vaccination rates in Arizona. Using school-level data from Arizona sixth-grade schools (n = 749), we regressed average sixth-grade school-level immunization rates on presence of a school nurse (registered nurse [RN] or licensed practical nurse [LPN]) and school-level socioeconomic status (SES), controlling for other school- and district-level characteristics. Schools with a nurse had higher overall vaccination rates than those without a nurse (96.1% vs. 95.0%, p < 0.01). For schools in the lowest SES quartile, the presence of a school nurse was associated with approximately 2 percentage point higher immunization rates. These findings add to the growing literature that defines the impact of school nurses on student health status and outcomes, emphasizing the value of school nurses, especially in lower SES schools.