The objective of this study aimed to find out the students’ knowledge of lexical collocation and the sources of language exposures students received. This research was a qualitative study with descriptive design. The sample for this research, chosen by using random sampling, was a Year 12 class with 24 students from Senior High School 4 Wira Bangsa in West Aceh. The writer obtained the data by using a language exposure questionnaire and a collocation C-test. The data analysis concluded that (1) students’ mastery of lexical collocation is in the types of Adjective + Noun (25%), Verb + Noun (24%), and Verb + Adverb (23%), while the types of Adverb + Adjective (16%) and Noun + Verb (12%) are considered to be difficult to acquire and (2) the students’ language exposures are mostly sourced from school (English teacher and English class activities) and media (English songs and TV shows), while there were rare exposure coming from home and dormitory. The findings showed a good reference to describe and to understand students’ knowledge of lexical collocation and their sources of language exposures in order to help students build the memory-banks of collocation.