Research to date suggests that textual enhancement may positively affect the learning of multiword combinations known as collocations, but may impair recall of unenhanced text. However, the attentional mechanisms underlying such effects remain unclear. In this study, 38 undergraduate students were divided into two groups: one read a text containing typographically enhanced collocations (ET group) and the other read the same text with unenhanced collocations (the baseline text, or BT group). While reading, participants’ eye movements were recorded with an eye-tracker. Results showed that the ET group spent significantly longer time processing target collocations, and performed better than the BT group in a post-reading collocation test. However, apart from the enhanced collocations, the ET group recalled significantly less unenhanced text than the BT group. Further investigation of eye fixation data showed that the ET group spent substantially longer time processing collocations which, according to a pretest, they were not familiar with than did the BT group, whereas the two groups did not differ significantly in their processing of familiar collocations. Collectively, the results suggest that the trade-off between collocation learning and recall of unenhanced text is due to additional cognitive resources being allocated to enhanced collocations that are new to the reader.