How is membership in the Academy of Motion Picture Arts and Sciences determined?

Answer 1

All members must be invited to join. Invitation comes from the Board of Governors. Membership eligibility may be achieved by a competitive nomination or a member may submit a name based on other significant contribution to the field of motion pictures.

Answer 2

The Academy of Motion Picture Arts and Sciences (AMPAS) chooses its members by committee. Generally, they invite filmmakers of prominence. Filmmakers who have been nominated or won an Academy Award are eligible for membership, but so are many other prominent filmmakers, see related questions below.

Answer 3

The members of the Academy of Motion Picture Arts and Sciences (basically, people who are involved in the making of movies, so actors, directors, cinematographers, etc.) vote on the nominees, and whoever gets the most votes wins.

Membership in AMPAS is by invitation only based on the recommendation of existing members, but being nominated for an Academy Award pretty much guarantees an invitation.