Wat Si Saket is a Buddhist wat in Vientiane, Laos. It is situated on Lane Xang Road, on the corner with Setthathirat Road, to the northwest of Haw Phra Kaew.

Wat Si Saket was built in 1818 on the orders of King Anouvong, which may be the oldest temple still standing in Vientiane. It was built in the Siamese style of Buddhist architecture, with a surrounding terrace and an ornate five-tiered roof, rather than in the Lao style, keeping it safe from the armies of Siam which sacked Vientiane in 1827.