The Apostolic Vicariate (or Vicariate Apostolic) of Vientiane (Latin: Vicariatus Apostolicus Vientianensis; Lao: ອັກຄະສາວົກແທນຂອງນະຄອນຫຼວງວຽງ) is a territorial jurisdiction of the Catholic Church located in northern Laos.

As an apostolic vicariate, it is a pre-diocesan jurisdiction, entitled to a titular bishop, and it is exempt, i.e., not part of any ecclesiastical province and instead directly dependent on the Holy See through the Congregation for the Evangelization of Peoples.

The vicariate dates back to the Apostolic Prefecture of Vientiane and Luang-Prabang, which was created on June 14, 1938, by splitting off the northern part of the Apostolic Vicariate of Laos.

On March 13, 1952, it was elevated to an Apostolic vicariate and renamed Vientiane after its largest city, the Laotian national capital.

The northern part around Luang Prabang was split off on March 3, 1963, to establish the Apostolic Vicariate of Luang Prabang, which since then has often been held in personal union with Vientiane or by an Apostolic administrator.