The information horizon is a mental map where users position their information sources in different contexts and situations, and the social network is one of the critical concepts in information horizons. Previous research on undergraduate and graduate students' information horizons has revealed that various human sources are used in academic or career-related contexts (Sonnenwald, Wildemuth. & Harmon, 2001; Tsai, 2010). While most literature shows that stronger tie sources are more likely to be used as a preferred or primary information source (Steffes & Burgee, 2009), Granovetter (1973) emphasizes the importance of "the strength of weak ties" in information diffusion. This study aims to examine undergraduates' social networks in their coursework-related information horizons as well as to investigate how strong and weak ties are positioned in their information horizons. A pretest of a web survey with 18 responses and 3 brief follow-up interviews were conducted with an undergraduate class at a large state university. After the pretest, fifteen undergraduate students were recruited to participate in the study. Results showed that undergraduate students tend to rely more on their colleagues and teaching assistants than on professors when they have questions on coursework-related issues. While stronger ties may be more frequently consulted for moral support, the tie strength does not necessarily determine the frequency of consultation about other coursework-related issues.