The influence of test anxiety on academic difficulties has been investigated in typically developing students, but the mechanism underlying the influence remains unclear, especially for those with specific learning disabilities (SpLDs). This study examined the role of metacognition in the relationship between test anxiety and literacy difficulties among Chinese typically developing adolescents as well as those who have been identified as having an SpLD and significant literacy difficulties (i.e., typically functioning SpLD) and without significant literacy difficulties (i.e., high-functioning SpLD) in Taiwan. A total of 238 first-year undergraduate students were recruited from eleven universities in South Taiwan. Among 238 students, 105 were identified to have SpLDs, and 133 were typically developing students. These students were asked to complete questionnaires on demographics, test anxiety, metacognition, and literacy difficulties (i.e., reading and writing). Structural equation modeling analyses showed that test anxiety among Chinese adolescents was linked to literacy difficulties but that only high-functioning and typically functioning students with SpLDs experienced a direct effect (without mediation by other factors). For those without SpLDs, the influence of test anxiety on literacy difficulties was not direct but significantly mediated by metacognition. Various components of these students' metacognition had mediating effects on different literacy difficulties. Test anxiety might influence the reading and writing difficulties of typically developing adolescents and those with typically functioning and high-functioning SpLDs through different mechanisms. Moreover, teachers at the university level are encouraged to consider students' test anxiety and metacognition when preparing their teaching materials.