WaveNet is a deep generative model for generating raw audio waveforms, while Tacotron is an end-to-end text-to-speech synthesis system. WaveNet focuses on generating high-quality audio by modeling the conditional probability distribution of audio samples, whereas Tacotron converts text directly into speech by predicting mel spectrograms from input text. In some cases, Tacotron can be combined with WaveNet to create a complete TTS system, where Tacotron generates mel spectrograms and WaveNet converts them into raw audio waveforms.