The Apostolic Vicariate (or Vicariate Apostolic) of Vientiane (Latin: Vicariatus Apostolicus Vientianensis; French: Vicariat apostolique de Vientiane) 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 Apostolic Vicariate's episcopal cathedral see is Sacred Heart Cathedral in Vientiane, one of the country's largest churches. Cardinal Louis-Marie Ling Mangkhanekhoun is its apostolic vicar.

The vicariate covers 74,195 km² in the civil Laotian provinces of Houaphan, Xiangkhoang, Vientiane Province, Vientiane Prefecture and most of Bolikhamsai.

As per 2014 it pastorally served 14,947 Catholics (0.7% of 2,216,558 total) in 23 parishes with 5 priests (1 diocesan, 4 religious) and 24 lay religious (4 brothers, 20 sisters).

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.

• List of Catholic dioceses in Laos

• GCatholic, with Google satellite photo
• Catholic hierarchy