This paper presents an experimental investigation of the narratological concept of narrative closure. While narrative closure is a well-studied phenomenon in contemporary narratology, it still lacks a serious empirical foundation. In order to fill that lacuna, we performed a controlled rating experiment aimed at validating some of the properties of narrative closure proposed in the narratological literature. Our results suggest that narrative closure is closely related to two connected properties: to the completeness of the text and to questions left open by the text.