ABSTRACT Purpose Research on digital game-based vocabulary learning (DGBVL) has rapidly grown. Most of these studies have overlooked note use based on two tacit assumptions: (a) learners do not need notes in DGBVL, and (b) note use reduces the effectiveness of DGBVL. However, evidence suggests that vocabulary learners may need notes, and note use can promote vocabulary knowledge development in various settings, which may be generalised to DGBVL. Methodology To test the assumptions and gain a deeper understanding of DGBVL, we conducted a study involving 50 Chinese university students who learned vocabulary in a DGBVL programme that allowed note use. Data were collected using a Tobii X2-30 eye tracker, tests of productive vocabulary knowledge, and interviews. Findings The finding showed that in note-allowed DGBVL, learners actively used notes and created six types of note content: spellings, meanings, L1 equivalents, word learning strategies, parts of speech and example phrases and sentences. Writing example phrases and sentences in notes significantly promoted vocabulary knowledge development, while word spellings in notes and frequent fixations on notes had the opposite effects. Originality Based on the findings, we reject the two tacit assumptions of note use in DGBVL and suggest explicit training on note use in DGBVL.