The basic rule regarding the deduction of legal fees is that you can deduct attorney’s fees you pay to produce or collect taxable income, or help determine, collect, or obtain a refund of any tax.
Generally, the legal fees you pay while trying to make child support payments non-taxable are deductible. In addition, your legal fees from attempting to collect support payments owed by a current spouse, former spouse, common-law partner or the natural parent of the child are also deductible.
Unfortunately, if you are the one who is required to pay child support, you are not entitled to any deduction for defending a child support claim, defending enforcement proceedings or bringing an application to change or reduce child support. The legal fees you pay to get a separation or divorce or to establish custody or visitation arrangements for a child cannot be claimed as tax-deductible. If you pay child support, you cannot claim any of the legal costs incurred to establish, negotiate or contest the amount of the support payments.