The articles in this special section focus on machine learning acceleration. In recent years, machine learning (ML) has become one of the most important pillars of computing industry, driven by the remarkable advances in the ML algorithms coupled with innovation in high performance computer architecture, as typified by GPUs. These advances in tandem propelled ML to a new era of real-world applicability and impact in almost every aspect of the IT industry. As the importance of ML in the emerging applications increases, the ML accelerators have become a critical component of every modern computing system, from data centers to mobile/IoT devices.