The modulo operator (%) in Python returns the remainder of a division operation. It takes two operands and calculates how much is left after dividing the first operand by the second. For example, 7 % 3 would result in 1, because when 7 is divided by 3, the remainder is 1. The modulo operator is commonly used in tasks like checking if a number is divisible by another (e.g., x % 2 == 0 checks if x is even) or wrapping around values in circular structures. It works with integers and floats, and the result has the same sign as the divisor.