While Virtual Reality applications attract the attention of developers and business analysts, the behavior of users watching 360-degree videos with Head-Mounted Display (HMD) has still to be understood. This paper introduces a dataset of the head movements of users who watch omnidirectionnal videos with a HMD. The dataset was collected on 59 users (including 20% of women) with the Razer OSVR HDK2 HMD. We used five 70 s-long 360-degree videos. These videos span a wide range of 360-degree content, including tourism, thrill, and discovery, for which different viewer’s involvement, thus navigation patterns, could be expected. We describe the open-source software that we developed to produce this dataset, present the test material and the viewing sessions conditions. We release the source code of the software to enable the community to extend the dataset. Finally we show a typical analysis of the dataset to exhibit some key characteristics of the used videos, and to show some users movement statistics.