Background Studies: Captioning and repetition are widely used multimedia instructional devices for non-native students. Generally, studies in this area have tended to focus on second language literacy skills rather than on learning new content knowledge. Additionally, posttests were administered immediately after the treatments, while the delayed influences of captioning and repetition have never been investigated. Objectives: This paper addressed these research gaps in two separate studies. More specifically, this study attempted to examine the influences of captioning and repetition on non-native students' immediate and relayed retention. Methods: In Study One, three captioning conditions; word-by-word captions, closed captions, and no-captions; were compared to examine their efficacies in immediate and delayed content knowledge retention on 82 Chinese university students. To address the limitations in Study One as the multimedia lesson was short and played only once, Study Two incorporated captioning and two repetition types in its design. One hundred and eleven Chinese university students watch a video lesson in one of four captioning and repetition conditions. Results: The statistical analyses of Study One indicated that there were no significant differences in both immediate and delayed retention test scores across the three captioning condition. Similarly, in Study Two, there were no significant differences in retention tests scores across the four captioning and repetition conditions. Findings: Neither the availability of captions nor the repetition types had any impact on the Chinese students' immediate or delayed content knowledge retention, which lent support to existing studies. Based on the research results, the limitations and future study possibilities are discussed.