Pastaza Quichua (PQ) is a member of the Quechua IIB branch of Quechuan languages and has a rich morphology. However, this richness is often over-simplified for the sake of simpler explanation. Most Quechuan languages have a morpheme that is usually spelt -ga, -ka or -qa, and is described as a topicalizing clitic. In this thesis, I will examine the morpheme -ga in PQ, which, like its cognates, is often said to be a topicalizing clitic, despite the fact that it frequently breaks traditional rules for both topic marking and clitic-hood. I find that -ga is a topic marker according to Büring’s (2016) description of topic, and that it is also a clitic according to Spencer & Luís’s (2012a) criteria of canonical clitics. I also describe some of the most common functions and usages of -ga, such as its frequent occurrence in topic-switching questions and its role in marking the context of a phrase.