The integrity of advertising rests on the level of compliance of its practitioners to stipulated codes of ethics that guide the advertising business. This study assessed the level of compliance of three Nigerian newspapers to the advertising codes stipulated by the Advertising Regulatory Council of Nigeria (ARCON). Specifically, compliance to five key codes: employment and business opportunities, drugs, identity, price, and competing products were content analyzed in The Nation, the Daily Sun and the Vanguard from January to December 2021. Results showed a significant breach of these advertising codes by the three newspapers. Specific cases of breaches of ARCON Code uncovered included failure on a number of occasions to fully identify the advertiser, use of wrong sign off, outright omission of sign off, failure to include prices of advertised products, etc. Consequently, we argue that the Nigerian mass media should be more socially responsible by vetting all advertisements before publication. This is to shore up the present low level of adherence to ARCON codes reported in the study. The work broadens our understanding of the level of media’s compliance to advertising regulations in an African context.