Systemic functional linguistics (SFL) studies how a language functions in a social context, concerning the meaning of clauses at three different levels: interpersonal, ideational, and textual. The aim of this corpus-based research is to find out the logical structures of clauses in Pakistani academic writings by evaluating two main elements of clause complexity: taxis and logico-semantics relations. For this purpose, Halliday & Matthiessen’s (2014) system of clause complexing was employed as an analytical framework. A sample size of 100 argumentative essays was taken from the ICLE corpus, which was written by Pakistani students. This corpus was annotated by using the UAM corpus tool manually. Furthermore, the comparative distributions of different types of clause complexes were studied and evaluated accordingly. It helped to identify and understand lexico-grammatical variations at the clause level in non-native Pakistani academic writings. The findings showed that Pakistani students composed hypotactic and paratactic with almost the same ratio in their writing with a minor deviation. They also tend to build different types of logico-semantic relations of clauses during the argumentation; however, the occurrences of expansion were high in contrast to projection. The null hypothesis was tested by deploying the Wilcoxon signed rank test. It revealed no significant difference between paratactic and hypotactic approaches. However, their various logico-semantic relations displayed significant differences (p<0.05).