Objective: To assess olfactory function in children and to create and validate an odor identification test to diagnose olfactory dysfunction in children, which we called the Universal Sniff (U-Sniff) test. Study design: This is a multicenter study involving 19 countries. The U-Sniff test was developed in 3 phases including 1760 children age 5-7 years. Phase 1: identification of potentially recognizable odors; phase 2: selection of odorants for the odor identification test; and phase 3: evaluation of the test and acquisition of normative data. Test—retest reliability was evaluated in a subgroup of children (n = 27), and the test was validated using children with congenital anosmia (n = 14). Results: Twelve odors were familiar to children and, therefore, included in the U-Sniff test. Children scored a mean ± SD of 9.88 ± 1.80 points out of 12. Normative data was obtained and reported for each country. The U-Sniff test demonstrated a high test—retest reliability (r ₂₇ = 0.83, P <.001) and enabled discrimination between normosmia and children with congenital anosmia with a sensitivity of 100% and specificity of 86%. Conclusions: The U-Sniff is a valid and reliable method of testing olfaction in children and can be used internationally.