Voice is considered essential in academic writing, and metadiscourse is an important device contributing to voice. This study explores the use of metadiscourse and voice construction in Bachelor of Arts (BA) theses written at the onset and final stages by university undergraduates majoring in English in China. A corpus consisting of the discussion sections in the first and final versions of 35 BA theses was built, annotated, and analyzed. Two academics from this university were then invited to evaluate 10 pairs of the texts and specify textual elements that conveyed voice and to provide further comments in a follow-up interview. Results showed that the students used significantly more evidentials, hedges, and boosters in the final versions. The reviewers perceived minor growth in voice strength from the sample texts, and they commented that both content-related features and metadiscourse contributed to voice. This study highlights the importance of cultivating undergraduates' awareness of voice construction and the use of metadiscourse in academic writing.