The systematic study of music-induced emotions requires standardized measurement instruments to reliably assess the nature of affective reactions to music, which tend to go beyond garden-variety basic emotions. The GEMIAC provides such tool - a checklist for rapid assessment of music-induced affect, designed to extend and complement the Geneva Emotional Music Scale. The checklist contains a selection of affect and emotion categories that are frequently used in the literature to refer to emotional reactions to music. The development of the checklist focused on an empirical investigation of the semantic structure of the relevant terms, combined with fuzzy classes based on a series of hierarchical cluster analyses. Two versions of the checklist for assessing the intensity and frequency of affective responses to music are proposed.