Canadian Union of Public Employees (CUPE) is a union that represents academic or non-academic employee groups at York University. Research assistant positions are not CUPE positions.

The four academic employee groups representing faculty at the University are: 

• CUPE 3903 Unit 1: All part-time employees registered at the University as full-time graduate students employed in teaching, demonstrating, tutoring or marking.
• CUPE 3903 Unit 2: All part-time employees employed in teaching, demonstrating, tutoring or marking, who are not registered at the University as full-time graduate students.
• CUPE 3903 Unit 3: All part-time employees registered at the University as full-time graduate students who are receiving financial assistance and are employed in administrative, clerical and research work.
• CUPE 3903 Unit 4: Part-time librarians and archivists.

The three non-academic employee groups representing staff at the University are:

• CUPE 1356: Full-time employees engaged in maintenance services and plant operations except Supervisors and above, office staff, students, part-time, or employees covered by other bargaining units.
• CUPE 1356-1: All security officials and parking officers except Supervisors and above, and except those employees represented by CUPE 1356-2.
• CUPE 1356-2: Part-time, casual York Student Safety Services employees in departments of Community Safety and Parking Services.