The national requirements for individual membership in a local Chapter are as follows. These are the minimum requirements; Chapters may elect to have stricter standards but not lower ones. Students are encouraged to participate in Mu Alpha Theta club meetings and activities, even if they do not qualify as Full members.

Full Membership, High School Chapter: High school students in grades 9 through 12, at the school where their permanent record resides, who have completed the equivalent of four semesters of college preparatory mathematics and in addition have completed or are enrolled in a still more advanced course, are eligible for full membership providing their mathematical work was done with distinction. On the 4-point grading scale, this shall mean at least a 3.0 grade point average.

Full Membership, Two-year College Chapter: Two-year college students who were members of Mu Alpha Theta in high school are eligible for membership in their college's chapter. Students are also eligible if they have had at least one mathematics course at or above the College Algebra/ Precalculus level with a 3.0 GPA overall in all two-year college mathematics courses at or above the College Algebra/Precalculus level.

Associate Membership: High school students in grades 9 through 12, at the school where their permanent record resides, who have completed two semesters of algebra or the equivalent with distinction and are enrolled in, or have completed, a semester of geometry or of second year algebra, are eligible for associate membership. Associate members do not pay the initiation fee, but should be registered with the national office so that they may attend the National Convention or compete in National competitions. They are not entitled to vote on national policy, however. They are entitled to attend and be heard at meetings and presumably are likely candidates for full membership.