This study aimed at determining the prevalence, pattern, sociodemographic features and effect on the quality of life of sinonasal diseases among the primary school children. This community-based descriptive cross-sectional study of school children with sinonasal diseases was carried out between October 2017 and March 2018 in Ibadan-Nigeria, using multistage sampling technique. Data was taken using a pretested, interviewers assisted questionnaire and statistically analyzed using SPSS IBM version 23.0. The prevalence of sinonasal diseases was 21.7% (n=964). Age range was 5-13 years; the mean age was 8.5±2.7. There were 52.6% males and male to female ratio was 1:1. Common sinonasal diseases were allergic rhinitis (37.8%), chronic rhinosinusitis (19.6%), nasal trauma (15.3%), acute rhinosinusitis (11.0%) and foreign body impaction (5.74%). Bilateral sinonasal diseases occurred in 82.3%. Right and left sinonasal diseases accounted for 10.0% and 7.7% respectively. Major presenting complaints were rhinorrhea (73.2%), excessive sneezing (36.4%), nasal blockage/stuffiness (32.5%) and itching (29.7%).Associated complications of sinonasal diseases were mainly orbital complications in 30.1%, pharyngitis in 12.9%, pneumonia in 8.6% and otitis media in 6.7%. Commonly affected qualities of life were fatigue (16.3%), sleep disturbance (12.4%), changes in mood (10.5%) and isolation (8.6%). The prevalence of sinonasal diseases in primary school children was 21.7%. At presentation the majority of the pupils had associated complications and affectation of the quality of life.