This paper intends to highlight the role indigenous language plays to enhance National harmony in Nigeria. Nigeria is a country with many ethnic groups where majority use their indigenous languages in communication, it is the most vital instrument of communication process and the orbit which man’s social, political, economic and environment endeavor revolve. There are various forms of social ill behavour in the country such as conflicts, kidnapping, harassment, abduction, violence, terrorism, disputes, armed robbery, ritual killings, land disputes, etc. in our country Nigeria today. The government at various levels took various measures to tackle the problems but it has yielded little or no result. All these constitute lack of harmony; therefore, this paper identifies the importance of Nigeria languages for National harmony and recommends among others the need for an enlightenment campaign as well as constituting a committee of language experts. Finally, the paper ended with conclusion and made some recommendations for boosting national harmony through indigenous language.