The criminalization of offensive, privacy-intrusive behavior is an important form of privacy protection. However, few studies exist of visual observation in criminal law. We address this gap by researching when nonconsensual visual observation is deemed harmful enough to trigger criminal sanctions, and on what basis the law construes the “reasonableness of remaining unobserved,” through a nine-country comparative study. We distinguish between voyeurism-centric approaches (focusing largely on nudity and sex) and broader, intrusion-centric approaches (such as observation inside closed spaces). Both approaches explicitly or implicitly reflect “reasonable” privacy expectations, listing criteria for situations in which people can reasonably expect to remain unobserved or unrecorded. We present a framework for criminalizing nonconsensual visual observation, encompassing factors of technology use, place, subject matter, and surreptitiousness, supplemented by factors of intent, identifiability, and counter-indicators to prevent over-criminalization. This framework is relevant for protecting visual aspects of privacy in view of individuals' underlying autonomy interests.