Group of 33 has been used to refer to two different international groupings:

• G33 (industrialized countries), an international grouping that existed briefly in 1999, that superseded the Group of 22 in early 1999, and was itself superseded by the present G-20 major economies later that year
• G33 (developing countries), originally 33 countries; the G33 name stayed the same as new member countries were added

• Seleyang Baru
• Seleznevo
• Seleznyovo
• Seleznyovo, Leningrad Oblast
• Seleção
• Seleção Sub-20
• Self accelerating decomposition temperature
• Self-acceptance
• Self access language learning centers
• Self-acting incline
• Self-actualisation
• Self actualisation
• Self-actualization
• Self-adhering bandage
• Self adhesive
• Self-adhesive tape
• Self adjoint
• Self adjoint form
• Self adjoint operator
• Selfadjoint operator
• Self-administered survey
• Self Advocacy
• Self-advocacy
• Self-affinity
• Self against City