An equal sign or equal sign (=) is a mathematical symbol used to represent an equal sign. It was invented by Robert record in 1557. In an equation, the equal sign is placed between two (or more) expressions with the same value.

Pioneer pilot Alberto Santos = Dumont may use the European symbol equal sign in a person's first name, especially in a double bucket name, because he often uses the equal sign (=) instead of a hyphen between his two last names, but it seems that he prefers this practice to show equal respect for his father's French and mother's Brazilian.

In chemical formulas, two parallel lines representing double bonds are usually represented by equal signs.