An outbreak of Microsporum canis infection affected 12 persons in two elementary schools over a period of 48 days in 2012 in Slovenia. Epidemiological, microbiological, and animal investigations were conducted. We defined cases as pupils or employees with skin lesions and confirmed or probable M. canis infection, attending one of the implicated elementary schools. Two clusters of six primary and six secondary cases were included in an unmatched case-control study. Contact with an adopted stray kitten at a birthday party was identified as the most probable source of infection. Secondary cases were more likely to have participated in gymnastic classes with a primary case than controls and were also more likely to have touched an infected child. Prompt communication and implementation of adequate control measures after the primary cases occurred would have prevented the secondary cases in another school.