Recent years have witnessed an increasing number of English-speaking students studying abroad in China. Whether these students can learn and reflect in their behaviors certain uniquely Chinese-style speech acts during their sojourn in China merits investigation. This paper reports on a case study investigating what and how four American university-level students developed knowledge and skills of compliment responding in Mandarin Chinese when they were participating in an 8-week intensive summer language program in Shanghai. Among the four participants, two were from a 2nd-year Mandarin Chinese class and two from a 3rd-year class. The qualitative data were collected from one pre-study questionnaire, weekly semi-structured interviews (a total of 6 for each participant), participants’ weekly reflective blogs, and the researcher’s observation of participants’ social interaction with native speakers of Mandarin Chinese. The results showed that despite their similar academic, linguistic, and cultural background, each participant experienced a heterogeneous and dynamic developmental process and developed different awareness and skills of compliment responding in Mandarin Chinese throughout the study abroad program. The researcher discussed how each participant’s agency and individual social interaction with native speakers of Mandarin Chinese as well as local Chinese residents’ socialization efforts during the study abroad program intertwiningly shaped what and how the participants learned about Mandarin Chinese compliment responding strategies.