We consider the problem of extending the classical S-lemma from the commutative case to noncommutative cases. Precisely, we extend the S-lemma to three kinds of noncommutative polynomials: noncommutative polynomials whose coefficients are real numbers, noncommutative matrix-valued polynomials, and hereditary noncommutative matrix-valued polynomials. Different from the commutative case, the S-lemma for noncommutative polynomials can be extended to the case involving multiple quadratic constraints. Some examples are given to demonstrate the relations between these newly derived conditions.