ABSTRACT Thesis Title: Transitivity Analysis of Suicidal Thoughts Posted Online Author: Adviser: Ana Mae A. Guintu Jaimee Marie B. Serrano This study analyzed ten suicidal ideations posted in the online forum, Reddit. Halliday's System of Transitivity was used to examine the ideational meanings of the posts, along with the elements of the clauses to achieve the purposes of the study. The study aimed to (a) discuss how the language of the texts are described in terms of Process, Participants, and Circumstance, and (b) unravel the language reflected in the discourse of suicide online. The study employed qualitative methodologies to provide an in-depth analysis of the language meanings and patterns from the corpus. Findings of the study revealed that Material Process, alongside its Participant function, was the most frequently used transitivity process having 126 clauses out of 387 total clauses. Meanwhile, the least observed transitivity process was behavioral, alongside its participant function, with only eight clauses. It was also revealed that material process was used to express not only the impact of the Actor's actions but also the actions performed to the Receiver (or Goal). Mental Process was used to express what is in the mind of the Senser, to express dislike in living and to express desire to depart this life.