The purpose of the present study is to contribute to the ongoing debate about the use of lexical bundles by first (L1) and second language (L2) speakers of English. The study consists of two experiments that examined whether L1 and L2 English speakers displayed any knowledge of lexical bundles as holistic units and whether their knowledge was affected by the discourse function of the lexical bundles (discourse-organizing or referential). The participants in Experiment 1 (N = 61) completed a gap-filling activity, whereas the participants in Experiment 2 (N = 61) carried out a dictation task. Results showed that the participants' knowledge differed for specific lexical bundles and that, overall, they knew more discourse-organizing bundles than referential bundles. The implications of the study are discussed in terms of current research about the role of frequency-based language chunks in L1 and L2 speech processing in English.