Abstract An orthonormal wavelets based equalizer (OWBE) is presented. The equalizer is represented by a set of orthonormal wavelets and the corresponding coefficients. The paper gives the structure and also the adaption algorithm of the OWBE. Theoretical analysis show that the OWBE convergences faster than the conventional FIR LMS based equalizer (LTE), while the increase in the computational complexity is very little. Several simulations are performed to evaluate the behavior of the OWBE.