Child Marriage is a topic which has raised so much public outburst and has caused a lot of controversies. It is a topic which comes with it a great deal of public emotions. Child marriage is tied to a number of factors including religion, traditions and customs. Child marriage usually refers to two separate phenomena which are practical in some societies. The first and most common practice is that of a young child being given out in marriage to an adult. In practice, it is almost always a young girl being married to a man. The second practice is a form of arranged marriage in which the parents of two children from different families arrange a future marriage. In practice, the individuals who become betrothed often do not meet one another till the wedding ceremony, which occurs when they are both considered to be of marriageable age. Whether a marriage is to be condemned for falling within the meaning of child marriage depends on whether such marriage is between an adult and a child. In other words, a marriage is enforceable only when it cannot be said to be a child marriage. The question that this raises therefore is, “what is the age limit for a valid marriage?” the answer to this question appears to be uncertain. The law has made an attempt in this regard. For instance in Nigeria, some statutes provide a specific age as the minimum age for marriage. The problem however is that there is no uniformity of application of these statutes. Indeed the law on age limit for marriage in the Southern Nigeria is not uniform with the Sharia law as it applies in some Northern parts of Nigeria. Again, the customary laws of the regions appear to apply different standards for determining marriageable age. This work attempts to examine the different enactments in force in Nigeria and how they apply with regard to marriageable age. It also attempts an examination of the customs of the three major ethnic groups in Nigeria namely Hausa, Igbo and Yoruba, and their practices on marriageable age with a view to determining the validity of theses customs based on the validity tests. The work also looks into the practices of other nations on child marriage and marriageable age. A solution on how uniformity of marriageable age can be achieved will be given at the end of the work. This work is divided into five chapters. Chapter one deals with the general introduction while chapter two deals with the overview of the statutes that provide for marriageable age in Nigeria. Chapter three deals with marriageable age under the Customary law while chapter four deals with the enforceability of age limit for marriage in foreign jurisdiction. Finally, chapter five deals with the conclusion and recommendations.