Short answer
Only fees expressly allowed by your agreement or by law. Adding unauthorized interest, collection fees or 'convenience' charges can violate the FDCPA and the Texas Debt Collection Act.
Helpful next
Sources
- Fair Debt Collection Practices Act, 15 U.S.C. §§ 1692–1692p (Cornell LII)
- Tex. Fin. Code ch. 392 (Texas Debt Collection Act), incl. § 392.307
Updated November 2026. General information about Texas law, not legal advice for your case. Laws and court rules change; we review these answers regularly.