Sathasivam Kanagaratnam is a Sri Lankan Tamil politician and former Member of Parliament.
In 2004 Kanagaratnam was selected by the Tamil Tigers as a Tamil National Alliance (TNA) parliamentary candidate. Kanagaratnam represented the Vanni multi-member electoral district for the TNA in the Sri Lankan Parliament between April 2004 and February 2010.
Kanagaratnam and his family were amongst the 300,000 civilians trapped in the No Fire Zone during the final months of the civil war. After the end of the civil war in May 2009 Kanagaratnam and his son were detained by the Terrorist Investigation Department of the Sri Lanka Police Service. Kanagaratnam was released in January 2010 after agreeing to support Mahinda Rajapaksa in the presidential election.
In 2010, after the Tamil Tigers' defeat in the civil war, the TNA deselected most of its Tamil Tiger appointed MPs, including Kanagaratnam. He subsequently joined the governing United People's Freedom Alliance (UPFA) and stood as one of its candidates in Vanni District in the 2010 parliamentary election. He failed to get elected, coming sixth amongst the UPFA candidates.