Tourists' information processing is a dynamic process in that their information use depends on the surrounding context. From tourists' personal characteristics (e.g., age, gender, and travel experience), nature of tourism products (e.g., intangibility and variability), to the development of information technology (e.g., the prevalent usage of mobile devices for information search), a variety of contextual factors are involved when tourists process information for decision-making. Given the importance of online reviews in the hospitality and tourism field as information sources, this dissertation aims to understand the contextual effects of online reviews on tourists' decision-making. By selecting several contextual factors, three independent and interrelated essays examine how tourists' cognitive or behavioral responses to online reviews are affected by those factors. Considering that local search (e.g., looking for nearby restaurants by using "restaurants near me" as a search query) becomes an important context for using online reviews, both Study 1 and 2 focus on the local search context. Study 1 investigates the role of online reviews in the local search context; specifically, how online reviews are used as ranking factors by local search platforms (LSPs), is examined with an analytical approach. Study 2 investigates tourists' processing of online reviews in the local search context; specifically, how online reviews are differently processed in the local search context (e.g., searching for a restaurant that can be visited immediately) compared with the non-local context (e.g., searching for a restaurant that can be visited in a month), is examined by conducting an experiment. Building on Study 2, Study 3 investigates how tourists' processing of online reviews is affected by another contextual factor, the nature of tourism products; specifically, how the variability of tourism products (i.e., their change in quality over time) influences the way tourists process online reviews, is examined through social media analytics. Results of the three essays provide empirical support for the underlying argument of this dissertation: understanding tourists' responses to online reviews depends on factors that transcend their information characteristics. As a whole, the findings of this dissertation suggest the need for considering the surrounding context to further understand how online reviews affect tourists' decision-making. As practical implications, this dissertation discusses the importance of leveraging various types of information about tourists' context (e.g., location accessed from smartphones, and physiological condition accessed through smartwatches). / Doctor of Philosophy / Tourists use online reviews within specific situations. The effects of such reviews on tourists' decision-making are difficult to explain without considering the surrounding contexts. Depending on when (e.g., before or during the trip), where (e.g., at home or destination), or for which products (e.g., restaurants, attractions, or hotels) they use online reviews, even the same online review can be differently perceived by tourists (e.g., how helpful it is). Therefore, the reviews have an increased or reduced influence on their product choices. This dissertation aims to understand the context-dependence of tourist's use of online reviews. The three essays in this dissertation examine how online reviews are used or processed by tourists under certain context: how online reviews affect tourist's decision-making in the local search context (e.g., searching for "restaurants near me" using smartphones during the trip) (Study 1); how tourists process online reviews while relying on reviews for immediately choosing places to visit (Study 2); and how tourists perceive online reviews when they are recently posted (Study 3). The findings confirm the dynamic nature of tourist's use of online reviews and offer several insights for tourism businesses to hone their strategies on marketing online reviews.