The 2003 floor crossing window period in South Africa was a period of 15 days, from 21 March to 4 April 2003, in which members of the National Assembly and the provincial legislatures were able to cross the floor from one political party to another without giving up their seats. The period was authorised by the passage of the Tenth Amendment of the Constitution of South Africa. The amendment scheduled regular window periods in the second and fourth September after each election, but the second and fourth Septembers after the 1999 election had already passed, so it included provision for a special window period starting fifteen days after the amendment came into effect.