Non-sinusoidal waveforms are waveforms that are not pure sine waves. They are usually derived from simple math functions. While a pure sine consists of a single frequency, non-sinusoidal waveforms can be described as containing multiple sine waves of different frequencies. These "component" sine waves will be whole number multiples of a fundamental or "lowest" frequency. The frequency and amplitude of each component can be found using a mathematical technique known as Fourier analysis.

Non-sinusoidal waveforms are important in, for example, mathematics, music and electronics.

Examples of non-sinusoidal waveforms include square waves, rectangular waves, triangle waves, spiked waves, trapezoidal waves and sawtooth waves.