Either parent may file a petition or motion to modify a child support order—upward or downward—but usually only when there is a substantial change in the child’s needs, or in one or both of the parents’ incomes or net resources, that justifies the court revisiting and possibly modifying the earlier child support order.

The petition or motion to modify child support generally must be filed in the same court that issued the original or most recent child support order. But if the child lives in a different county or state, the courts of the county or state where the child lives may be the proper place to file a petition or motion to modify a child support order.

In Maryland, either parent has the right to file a petition or motion to modify an existing child support order. This can be done when there is a significant change in circumstances, such as a substantial shift in the child's needs or a notable change in the financial situation of either parent. The law requires that the change must be substantial and continuing to justify a modification of the child support order. Typically, the petition or motion to modify the child support must be filed in the same court that issued the original or most recent order. However, if the child has since moved to a different county or state, the modification may need to be filed in the jurisdiction where the child currently resides. Maryland courts will consider the best interests of the child, the current Maryland Child Support Guidelines, and any significant changes in circumstances when reviewing a petition for modification.