Background and objectives: Head louse, also known as Pediculus humanus capitis, is an obligate ectoparasite that is a distributed all around the world. The aim of present study was to determine the prevalence of head lice infestation in primary school students in Tabriz, East Azerbaijan Province, Iran.
Methods: Overall, 3,032 students (1,515 boys and 1,517 girls) from 33 primary schools in Tabriz were selected via multi-stage cluster sampling in 2018. The students were examined individually and privately by experts. Head lice infestation was confirmed by detecting adult or nymph or nits less than 1 cm from base of hair. Data analysis was carried out in SPSS software package (version 23). Association of participants’ characteristics with pediculosis infestation was evaluated using logistic regression and chi-square test at significance level of 0.05. 
Results: Head lice infestation was present in 130 (4.29%) students, while the prevalence of this condition was higher in girls (2.11%) than in boys. The highest prevalence (6.05 %) was observed in children age 6 years old regardless of gender. The rate of head lice infestation was lowest among students aged ≥12 years (3.17%). There was a significant relationship between head louse infestation and parent’s occupation, family size, the frequency of combing and hair style.
Conclusion: Although the prevalence of head lice infestation in Tabriz is relatively low, screening and treating schoolchildren should be done continuously in order to reduce the infestation rate.