This paper reports on an exploratory study that investigated the relationship between English as a foreign language (EFL) writers’ reported metacognitive strategy knowledge and their English writing performance in multimedia environments in a Chinese tertiary context. A self-report questionnaire was used to collect data on 126 participants’ metacognitive strategy knowledge and EFL writing scores. Mann-Whitney U Tests were conducted to explore differences between high (n = 65) and low (n = 61) EFL proficiency groups. Analysis of the data revealed that the participants’ metacognitive strategy knowledge was correlated significantly with their writing performance. The high EFL-proficiency group reported having statistically significantly more metacognitive knowledge about three clusters of metacognitive strategies (planning, monitoring, and evaluating) than their low EFL-proficiency counterpart. These important findings point to pedagogical implications that there is a need to integrate metacognitive strategies into teaching and researching EFL writing.