Writing native-like has always been a primary purpose for non-native writers of English and, accordingly, many language components have been investigated to develop writers' fluency. One of these language components is syntactic complexity (SC), which is often regarded as a reliable way to grade any texts from easy to difficult. This study aims to compare native and non-native writers' fluency by measuring their SC and to create a reference SC point for non-native writers of English. To achieve this, the study comprised two groups: Group 1 was composed of native speakers from Inner-circle countries, namely USA, England, Canada, and Australia, and Group 2 was composed of non-native speakers from Expanding countries, namely Turkey, Saudi Arabia, Russia, and China. The data were composed of 200 MA dissertations in ELT equally collected from countries in Group 1 and Group 2. SC realisations were divided into 14 subcategories. The 14 sub-categories constituted a taxonomy for SC and they were analysed through ANOVA, Kruskal-Wallis, Independent sample t-test, and Mann-Whitney tests. The results showed that there is a statistically significant difference in 9 categories in favour of Group 1 and that the average SC scores of Group1 are significantly high compared to Group 2. The study suggests that writers of MA dissertations pay particular attention to SC, if native-like fluency is sought because it was concluded that native writers of MA dissertations are prone to write with higher SC level when compared to non-native writers of MA dissertations.