The extended use of the Internet has produced new forms of victimization for children and youth, among which online sexual abuse stands out. The study of this form of victimization is frequent worldwide, but there is a lack of brief instruments in Spanish language which also offer good psychometric properties. The objective of the present study was to examine the factorial structure and intercultural factorial invariance of a brief scale of online sexual abuse. The participants were 1,502 adolescents from Spain and Chile between 15 and 17 years. The results of exploratory factor analyses with a proportion of the Spanish sample (n= 698) suggest that the 12-item scale has a single factor structure and adequate internal consistency. Confirmatory factor analyses with a second proportion of the Spanish sample (n= 402) and with the Chilean sample (n= 402) corroborate the unifactorial structure in both countries. The results support the configurational factorial invariance, but not the strict factorial invariance. We discuss the implications of the results when using the scale in both countries and making comparisons between them.