| Honorific-Prefix: | Honourable |
| S. Shanmuganathan | |
| Honorific-Suffix: | MP |
| Constituency Mp: | Vanni District |
| Parliament: | Sri Lanka |
| Term Start1: | 1994 |
| Term End1: | 1998 |
| Birth Place: | 16 May 1960 |
| Nationality: | Sri Lankan |
| Party: | Democratic People's Liberation Front |
| Otherparty: | People's Liberation Organisation of Tamil Eelam |
| Blank1: | Ethnicity |
| Data1: | Sri Lankan Tamil |
Sarawanabavanandan Shanmuganathan (16 May 1960 - 15 July 1998; known as Vasanthan) was a Sri Lankan Tamil militant, politician and Member of Parliament.
Shanmuganathan was born on 16 May 1960.[1] He was a Hindu.[1] He was a senior member of the militant People's Liberation Organisation of Tamil Eelam, serving as its commander in Vavuniya.[2]
Shanmuganathan was member of Vavuniya Urban Council.[3] He contested the 1994 parliamentary election as one of the Democratic People's Liberation Front's candidates in Vanni District and was elected to Parliament.[4]
Shanmuganathan was killed by a claymore mine in Irambaikkulam, Vavuniya District on 15 July 1998.[3] [5] The assassination was blamed on the rival rebel Liberation Tigers of Tamil Eelam.[6] [7] However, the pro-LTTE TamilNet claimed that Shanmuganathan had been the victim of an internal conflict within the PLOTE.[8]