Windfall Profits Tax Act of 2005

Windfall Profits Tax Act of 2005 - Amends the Internal Revenue Code to impose an excise tax on certain oil companies for 50% of the windfall profit from all barrels of taxable crude oil. Defines "windfall profit" as the excess of the removal (sales) price of a barrel of taxable crude oil over the adjusted base price of such barrel ($40 per barrel adjusted annually for inflation). Allows a tax deduction for any windfall profit tax paid. Terminates the tax 10 years after the date of enactment of this Act.

Allows an income tax rebate for individual taxpayers of $150 in 2006 and, in subsequent years, of an amount to be determined by the Secretary of the Treasury based upon a percentage of windfall profit tax revenues collected.

Establishes in the Treasury the Low-Income Energy Assistance Trust Fund. Transfers windfall profit tax revenues to such Fund and provides for expenditures from such Fund for the low-income energy assistance program.

Allows a tax credit for investment in energy efficient motor vehicles and for related research and development costs. Bases the amount of such credit on the achievement of specified levels of fuel economy. Terminates such credit after 2015.