This study addresses the role of co-speech gestures in the construal of aspectuality. A behavioral experiment was conducted with speakers of Czech to investigate patterns observed in a preceding multimodal corpus-based study focusing on gesture and aspectuality. In particular, the experiment was designed to explore the perceived association between the emphasized ending of a hand movement (or absence thereof) and the grammatical aspect (and the lexical-semantic properties) of the predicate accompanied by the gesture. Combining various approaches in its design (motion capture, lexical ratings, corpus data), the experiment revealed a strong association between the perfective aspect and end-marking in gestures, while the link between the imperfective and gestures without a marked ending was weaker. The results of the experiment are in line with tendencies observed for other languages, indicating that the gestural marking of boundary is prominent in multimodal construals of events. Besides, specific multimodal patterns (combinations of finer-grained lexical-semantic features and formal parameters of gestures) also occur, as reflected in the data. This study provides the first experimental data on the perception of multimodal expressions in Czech.