Non-finite clauses are one of the elements considered as an index of syntactic complexity, which is a distinguishing feature of academic register. In this sense, the current study aims to reveal the frequency and syntactic functions of non-finite clauses in the academic writings of non-native and native English students. In order to reach this aim, a specialized corpus with two sub-corpora consisting of the MA and PhD theses of natives and non-natives was compiled. The native and non-native corpora were similar in terms of size and the topics of the texts. The data were analyzed using the Antconc concordancing tool, and the log-likelihood tool was used to calculate the significance of the findings. The result of the study showed that non-natives significantly underused the non-finite clauses in their academic texts compared to their native counterparts. Although there is a statistically significant difference in terms of the overall frequency of non-finite clauses, the distribution of the forms of the non-finite clauses was found to be balanced in NS and NNS texts. That is, both NSs and NNSs used bare infinitives less frequently and to infinitival most frequently in academic papers. In terms of the syntactic functions of the non-finite clauses, adjectival (adnominal) was used more frequently and nominals were used less frequently in both corpora. The findings of this study were compared with the previous findings, and educational implications were presented.