The best interests of the child refers to the factors most courts consider when making decisions on child custody and visitation rights.

These factors may include the needs and circumstances of the child (happiness, security, mental health, emotional development, educational opportunities, special needs, siblings, religious and cultural considerations, continuity and stability, child’s wishes) and the circumstances of the parent or caregiver (relationships, living arrangements, history of abuse, mental health, physical health, financial resources, substance abuse).

There is generally a presumption that it is in a child’s best interests to have a relationship with both of the child’s biological parents—unless one or both of the parents are shown to be unfit parents.

In New Mexico, as in other states, the 'best interests of the child' standard is the paramount consideration in making decisions about child custody and visitation rights. This standard is applied to ensure that the child's welfare is given the utmost priority. New Mexico courts consider various factors to determine what will best serve the child's needs and circumstances. These factors include, but are not limited to, the child's happiness, security, mental and emotional development, educational opportunities, any special needs, the presence of siblings, religious and cultural considerations, as well as the need for continuity and stability in the child's life. The child's own wishes may also be taken into account, especially if the child is of sufficient age and maturity. The courts also evaluate the circumstances of the parents or caregivers, including their relationship with the child, living arrangements, history of abuse or neglect, mental and physical health, financial resources, and any issues with substance abuse. While there is a general presumption in favor of maintaining a relationship with both biological parents, this presumption can be overcome if evidence shows that a parent is unfit. The primary goal is to foster and maintain an environment that is most conducive to the child's well-being.