Membership in the Philosophical Society of Texas is by invitation only. Active membership is limited to two hundred and fifty persons of distinction whose life and character have furthered the purposes for which the Society was established. Currently the Society has over 350 members, including associate and emeritus members. Only persons who reside within, were born within, or at some time have resided within the geographical boundaries of the Republic of Texas as set forth by the Congress of the Republic in 1836 are eligible for membership.