34 Tex. Admin. Code § 3.61
A credit is allowed to a person, firm, or corporation that, as a purchaser, has paid legally imposed sales or use tax to another state, including any political subdivision of that state, on a motor vehicle that later becomes subject to the Texas Motor Vehicle Use Tax. The credit allowed is the amount of the prior payment to the other state and any political subdivision of that state. If the purchaser is leasing a vehicle and paying the tax to another state along with the lease payments, credit can be allowed only for tax already remitted to the other state prior to operating the vehicle in Texas. Credit is not allowed for a foreign country's tax, custom or duty tax, or import tax. The purchaser can show a tax receipt, a seller's invoice, or contract verifying the amount of tax paid to another state and any political subdivision of that state. Credit is not allowed against the $90 new resident tax or the Texas Emissions Reduction Plan surcharge, set forth in Tax Code, § 152.0215. If a motor vehicle purchased tax-free for use solely outside Texas is later used inside Texas, use tax is due on the purchase price; however, credit is allowed in the amount of a legally imposed sales or use tax paid to another state and any political subdivision of that state.
34 Tex. Admin. Code § 3.61