The religion of one or both parents generally won’t be the basis for a court’s decision on child custody arrangements—due in part to the protections of the First Amendment to the United States Constitution—unless the evidence introduced in court shows the religious practices are abusive or will likely have a substantial harmful effect on the child, and will not be in the child’s best interest. In most circumstances parents with shared custody of their child will be free to engage in their choice of religious services and activities with the child during their time of custody.

In Massachusetts, as in other states, the best interest of the child is the paramount consideration in determining child custody arrangements. The First Amendment to the U.S. Constitution protects religious freedom, which means that a parent's religion alone is not a valid basis for determining custody. Massachusetts courts will not favor one parent over the other based on religious beliefs unless there is evidence that a parent's religious practices are harmful to the child or not in the child's best interest. When parents have shared custody, each parent is typically free to engage in their chosen religious activities with the child during their respective custody periods. However, if there is a concern that specific religious practices could be detrimental to the child's welfare, the court may consider this in its custody decision. The focus remains on the child's health, safety, and welfare rather than on the religious convictions of the parents.