Here we present the stimuli and results from a study on the effectiveness of a newly developed graphical subjective emotion assessment tool (the EmojiGrid) for the emotional evaluation of immersive VR systems. Immersive 360º VR systems are increasingly used in entertainment, marketing and design and development processes. Many of these applications involve emotional experiences. Since momentary emotions significantly determine a user’s response and decisions, it is essential to understand the influence of media content and technological factors on the user’s emotional response. Knowledge of this relation can serve to optimize media content and system characteristics to achieve the desired emotional states for the intended purpose. To measure the emotional responses to immersive VR experiences, efficient immersive and validated instruments are required. Most tools currently used to measure the emotional response of users compromise the immersive experience since they are cognitively demanding, time consuming, and their application requires the user to leave the VR. Here we investigated the convergent validity of the efficient and intuitive EmojiGrid graphical affective self-report tool for the assessment of valence and arousal evoked by videos representing 360º VEs (virtual environments). Using the EmojiGrid, 40 participants rated their emotional response to 62 videos from a validated public database representing 360º VEs, while their autonomic physiological arousal was simultaneously assessed through electrodermal activity. The mean affective ratings obtained with the EmojiGrid and those provided with the database (obtained with an alternative validated rating tool) show excellent agreement for valence and good agreement for arousal. The EmojiGrid mean arousal ratings correlate stronger with autonomic physiological arousal than the arousal ratings provided with the database. We conclude that the EmojiGrid is a valid and immersive affective self-report tool for the assessment of VE-evoked emotions.