A school-located mass vaccination program can enable rapid vaccination of a large number of students while minimizing disruption of their school activities. During 3 consecutive influenza seasons beginning in 2005, the Knox County Health Department conducted school-located mass vaccination clinics using live attenuated influenza vaccine. Overall, the proportion of elementary schoolchildren vaccinated with live attenuated influenza vaccine exceeded 40% each year. We describe key lessons learned in clinic operations, including obtaining informed consent, defining the organizational structure and roles, preparing the school, staffing, training, supplies, vaccine management, team communication, and data management. We conclude by discussing program costs and sustainability.