Non-self may refer to:

• Anatta, in Buddhist philosophy, the "non-self" or "absence of separate self"
• Open individualism, the philosophy that there exists only one numerically identical subject, who is everyone at all times, in the past, present and future.
• The distinction of self from non-self, a central concept in Immunology proposed by Macfarlane Burnet
• Exogenous antigen, a non-self molecule that stimulates an immune response