Determinants of firm innovativeness are said to be relatively understudied and little is written about firms from the oil industry within the context of African economies. This article attempts to fill that gap by investigating the impact of endogenous factors, particularly the impact of knowledge management practices (KMP) on the technological innovativeness of petroleum firms in Nigeria. Survey data collected from petroleum firms in Nigeria were used to examine the relationship between their technological innovativeness and the KMP engaged by the firms. Our analyses show that in the context of the study, KMP significantly impact the technological innovativeness of firms. The results were largely consistent with extant research on the role of knowledge management on the innovativeness of firms. Our findings provide valuable insights about knowledge as a strategic resource of the firm. Thus, undertaking the relevant KMP will enhance the technological innovativeness of petroleum firms operating in Nigeria.