The perspective from the parents of non-university students is essential in determining inclusive education in a school. The Index of Inclusion is one of the most widely used self-assessment tools and strategies to help teaching teams self-assess their political cultures and practices from the perspective of the values and principles of educational inclusion worldwide. For this reason, the present study intends to show evidence of validity of the Index for Inclusion questionnaire for parents of non-university education students, in a quantitative way, through a confirmatory factor analysis (CFA). In this study, 108 fathers and 500 mothers took part, aged between 21 and 62 years (M = 43.59; SD = 6.64), whose children belonged to educational institutions throughout Spain. The results revealed adequate adjustment rates, showing invariant structure with respect to sex. The Index for Inclusion for families of non-university education students was shown to be a robust and adequate psychometric instrument to assess the degree of development of inclusive education in educational institutions from the perspective of the parents of said student body. The family is a basic pillar in the education of children and a reference for them. In addition, parents of non-university education students are configured as fundamental participatory elements of the child's educational institution thus; making the family a fundamental element that favors inclusive education. Precisely because of all this, the future administration of this questionnaire (to the parents of these students) is recommended.