This book constitutes the proceedings of the 20th International Conference on Speech and Computer, SPECOM 2018, held in Leipzig, Germany, in September 2018. The 79 papers presented in this volume were carefully reviewed and selected from 132 submissions. The papers present current research in the area of computer speech processing, including recognition, synthesis, understanding and related domains like signal processing, language and text processing, computational paralinguistics, multi-modal speech processing or human-computer interaction.