Financial reporting aids the quality of financial statement as it plays a fundamental role in the functioning of an organization. Therefore, this study examined the effect of whistleblowing mechanism on financial reporting quality in quoted multinational oil and gas firms in Nigeria. A survey research design was adopted and data collected were analyzed using descriptive statistics and ordinary least square regression analysis. The Quality of financial reporting was captured by accuracy and reliability, transparency and disclosure, consistency and comparability, relevance and materiality and timeliness. From the result, a direct impact existing between whistleblowing and all the five variables was discovered. This result was also corroborated by the findings of the correlation matrix. The result shows that whistleblowing among quoted multinational oil and gas firms in Nigeria enhances high-quality financial information useful for better decision making, and above all promotes public trust. It was advanced that all agencies of the government, professional bodies coupled with the law enforcement agencies should work in harmony to protect whistleblowers as this will further enhance financial reporting quality among firms in Nigeria.