Purpose: The purpose of this paper is to present the understandings and administrative actions of six Catholic high school principals in relation to their administrative expectations of the admission of non-Catholic students. Design/methodology/approach: This paper involves interviews with six Catholic school principals from one Catholic school division in a Western Canadian province. The methodology chosen for this paper is grounded theory. Specific analytical processes are employed: open-, axial-, and selective-codings. Findings: The findings present four major themes with respect to the inclusion of non-Catholic students in their schools: the school administrators' expectations; the significance of the preliminary interview; the ongoing relationship of the non-Catholic student to the Catholic school; and points of confrontation with the Catholic school administration. Practical implications: The paper provides some guidance with respect to the application and entrance procedures which non-Catholic students should undergo before admission. It also points to the importance of providing information about the school's spiritual mission to non-Catholic parents before their child is admitted to the school community. Originality/value: The paper's originality lies in the findings offered in an area of education, which is not yet well researched. (Contains 1 table.)