National Internal Revenue Code (NIRC)
Section 23. General Principles of Income Taxation in the Philippines. - Except when otherwise provided in this Code:
(A) A citizen of the Philippines residing therein is taxable on all income derived from sources within and without the Philippines;
(B) A nonresident citizen is taxable only on income derived from sources within the Philippines;
(C) An individual citizen of the Philippines who is working and deriving income from abroad as an overseas contract worker is taxable only on income derived from sources within the Philippines: Provided, That a seaman who is a citizen of the Philippines and who receives compensation for services rendered abroad as a member of the complement of a vessel engaged exclusively in international trade shall be treated as an overseas contract worker;
(D) An alien individual, whether a resident or not of the Philippines, is taxable only on income derived from sources within the Philippines;
(E) A domestic corporation is taxable on all income derived from sources within and without the Philippines; and
(F) A foreign corporation, whether engaged or not in trade or business in the Philippines, is taxable only on income derived from sources within the Philippines.