Wavetable synthesis is a sound synthesis technique used to create quasi-periodic waveforms often used in the production of musical tones or notes. It uses a series of waveforms that are digitized as a series of amplitude values. Each waveform normally consists of a single cycle of the wave. Many such digitized waves are collected and stored in a table, often containing a series of slightly modified versions of an original "pure" tone.

To produce output, the system selects a starting point within the table and a length, and the system loops through that section of the stored waveforms and plays it repeatedly. Each amplitude value is read from memory in turn, often stored in ROM. The series of numbers being read is sent into an digital-to-analog converter, which converts the value into an electrical signal to produce an audible signal. Most systems include the capability to mix multiple samples together to produce more complex output.

One example of the technique is in the Waldorf Microwave synthesizer which had loadable wavetables. One consisted of the statement "nineteen twenty" from a voice synthesizer. By selecting different starting points and lengths within this sample, a wide variety of sounds can be produced.

Wavetable synthesis was invented by Max Mathews in 1958 as part of MUSIC II. MUSIC II “had four-voice polyphony and was capable of generating sixteen wave shapes via the introduction of a wavetable oscillator.”

Hal Chamberlin discussed wavetable synthesis in Byte's September 1977 issue. Wolfgang Palm of Palm Products GmbH (PPG) developed his version in the late 1970s and published it in 1979. The technique has since been used as the primary synthesis method in synthesizers built by PPG and Waldorf Music and as an auxiliary synthesis method by Ensoniq and Access. It is currently used in hardware synthesizers from Waldorf Music and in software synthesizers for PCs and tablets, including apps offered by PPG and Waldorf, among others.

It was also independently developed by Michael McNabb, who used it in his 1978 composition Dreamsong.

Electronic synthesizers using digital techniques generally produce sounds by producing a digital value, a number, and then sending that value to an digital-to-analog converter (DAC) that produces a scaled output voltage. For instance, to produce a triangle wave or sawtooth, systems used a register containing a starting value, normally zero, and then periodically increase or decrease the value using an adder or phase accumulator. The value in the register is continually sent to the DAC to produce output. The pitch of the resulting sound can be changed by how rapidly the adder is called.

Wavetable synthesis is a relatively simple modification of this sort of system. Instead of the value at any particular instantly being periodically modified by a simple function like addition, the specific value for any instant is read from memory containing a series of values making up multiple arbitrary, single-cycle waveforms. This allows the waveform to have any shape, not just simple ones like triangles or sines. With that exception, the system is otherwise the same; values are read into the register at a rate that produces the desired pitch, and the output of the register is used to feed a DAC that produces the output signal. In order to produce a different sound, all that has to be changed is a single value pointing to the starting point of the waveform in memory.