Nonpublic and homeschool students can participate in extra-curricular activities at a public school. Participation in these activities is subject to the same standards as full-time, enrolled students, including academic eligibility. The school principal verifies that the home school student meets academic eligibility, but cannot dictate educational philosophy, curriculum, textbooks, materials, time, place, method of instruction, or evaluation. The verification may not include any form of student assessment.

Montana Code Annotated § 20-5-112

  1. A school district or an athletic association, conference, or organization with authority over interscholastic sports may not prohibit or restrict the ability of a student attending a nonpublic or home school meeting the requirements of 20-5-109 from participating in extracurricular activities at a school in the student’s resident school district solely on the student’s enrollment at the public school or on the number of hours the student physically attends the public school.
  2. EXCEPT AS PROVIDED IN SUBSECTIONS (1) AND (3), a student attending a nonpublic or home school who participates in extracurricular activities at a public school is subject to:
    1. the same standards for participation as those required of full-time students enrolled in the school;
    2. the same rules of any interscholastic organization of which the school of participation is a member.
    1. The academic eligibility for extracurricular participation for a student attending a nonpublic school must be attested by the head administrator of the nonpublic school.
    2. The academic eligibility for extracurricular participation for a student attending a home school must be attested in writing by the educator providing the student instruction with verification by the school principal. The verification may not include any form of student assessment.

Montana Code Annotated § 20-5-101

As of July 1, 2024, homeschool students can enroll part-time in their resident school district. 

(8) The trustees shall assign and admit a child who is enrolled in a nonpublic or home school and who meets the requirements of subsection (1) as a part-time enrollee at the request of the child's parent or guardian.

Things to keep in mind:

Public school access includes participation in public school classes, sports, activities, etc.

States use a unique vocabulary in this area: “extracurricular,” “cocurricular,” “curricular,” “interscholastic,” “program,” “activity,” etc. Care should be taken to distinguish one from another. When a state defines a word, it is important.

While athletic association rules are not “law,” public schools are generally constrained to operate within them, or their teams could be disqualified.

We strive toward keeping this information 100% up to date in this rapidly changing area of the law. However, this post should not be considered authoritative because of the possibility of unobserved changes in association rules, statutes, regulations, or case decisions, and because of lag time between changes and the publication of updates.