Gas Price Relief Act of 2005 - Amends the Internal Revenue Code to impose an excise tax, for a one-year period, on oil companies for a percentage of the windfall profit from all barrels of taxable crude oil; (2) allow a tax deduction for the payment of any windfall profit tax; (3) reduce by 10 percent the excise tax on highway motor fuels for a period of one year after the enactment of this Act; (4) provide for transfers of windfall profit tax receipts and amounts from the general fund to the Highway Trust Fund; and (5) make adjustments to highway motor fuel taxes for floor stocks of such fuels held by dealers prior to, or after, the effective date of reduction in such taxes under this Act. Defines "windfall profit" as the excess of the removal (sales) price of a barrel of taxable crude oil over the base price ($40 per barrel) of such barrel.