Over a 5-year period from 2016 to 2020, this paper compares the value relevance of accounting numbers of banks and insurance firms listed on the Nigerian Stock Exchange market. The analysis used data from annual accounts of these companies and the Nigerian Stock Exchange facts sheet to apply Ohlson's (1995) valuation model to test the comparative value validity of accounting numbers of these two sub-sectors in the financial service industry. The findings of the empirical analyses revealed the importance of accounting information's value relevance to listed group financial service firms in Nigeria. Furthermore, the accounting numbers of banks have been found to be more important in terms of information quality than the accounting numbers of insurance firms. As a result, the paper proposes that firms' operations be sustained in order to improve profits, performance, and shareholder wealth.