Role-playing is changing one's behaviour to assume a role. This can be deliberately to act out an adopted role, or unconsciously to fill a social role.

The Oxford English Dictionary defines role-playing as "the changing of one's behaviour to fulfill a social role".^[1] However, in the field of social psychology, the term is used more loosely:

• To refer to the playing of roles generally, such as in a theatre or educational setting;
• To refer to taking a role of a character or person and acting it out with a partner taking someone else's role;
• To refer to a wide range of games including role-playing video game (RPG), play-by-mail games and more;
• To refer specifically to role-playing games.^[2]