Semantic roles denote different semantic relations that a noun phrase plays with respect to the action or state described by a predicate of a sentence. Semantic is another universal feature of language, if there is an event involving more than one participant, the speaker and the hearer care to know who is the agent, who is the patient or who is the experiencer and who is the stimulus. There seem to be some languages that, despite this obvious concern, do not mark semantic role in any consistent way. The key objective is to examine semantic role-marking in Lunyore morphology and syntax. Descriptive research design was adopted and the target population was the people of Emuhaya Sub county in Vihiga county. Purposive sampling technique was applied to gather head-marked phrases from churches, baraza sessions and Lunyore texts. The research instruments included conversations, written texts from Lunyore, participant and non-participant observations until saturation stage was attained. Data was analyzed through descriptive form. It was found that semantic role-marking was influenced by the morphological structure of the head-marked phrase. The study also found that there is a syntactic and semantic relationship in head-marked phrases. Theta theory was applicable in examining the semantic role marking in Lunyore head-marked phrases.