This study examines the Nigerian cultural values and edvertising ethics with a view to find out if some advertising agencies in Nigeria like; Prima Garnet, DDB Casers, Lintas, Noah’s Ark and Concept Unit are ethically based as well as if they reflect Nigerian culture in advertisements that they create. The specific objectives of this study were: (1) To ascertain if Prima Garnet, DDB Casers, Lintas, Noah’s Ark and Concept Unit advertising agencies create advertisements that portray Nigerian cultural values from the residents of Lagos, Abuja and Port- Harcourt. (2) To investigate among the residents of Lagos, Abuja and Port –Harcourt whether advertisements created by Prima Garnet, DDB Casers, Lintas, Noah’s Ark and Concept Unit advertising agencies were based on advertising ethics. (3) To identify which advertising agency reflects Nigerian cultural values in advertisements most among the residents of Lagos, Abuja and Port- Harcourt. The theoretical framework was the Dominant theories of Ethics. Survey was the research method used while the questionnaire was the instrument for gathering data for this study. The respondents for this study were purposively selected from three major cities which make up the three main ethnic groups or regions (Northern, Western and Eastern regions) in Nigeria. A total of 360 copies of the questionnaire were shared using stratified sampling technique into 120 copies for each state to be represented equally. This study concluded that there is a strong link between advertising and culture and this relationship should not be underestimated for positive advertising impact to be achieved. This study therefore recommends that, APCON should ensure that all advertisements portrayed in the mass media meet ethical standards of the profession and reflects the culture of the people of Nigeria.