Calauag, officially the Municipality of Calauag (Tagalog: [kaˈlaʊag]; Tagalog: Bayan ng Calauag), is a municipality in the province of Quezon, Philippines. According to the 2024 census, it has a population of 68,999 people.

According to the writings of Valentin Martin in his "Ensayo de una sintesis de los trabajos realizados sos las corporaciones religiosas Españolas de Filipinas", the first record of the establishment of a settlement in Calauag dates as far as the year 1584. However, the formal founding of the town by Spanish conquistadors was placed in the year 1851 with the union of the settlements in Apad and Calauag.

The first elected Captain of the town was Juan Sunog. In 1897 the town was placed the Revolutionary Government and Alipio Declaro became the Municipal President. In 1914 under Municipal President Marciano Roldan, the town was destroyed by fire for the first time in its history. On December 24, 1941, the town was occupied by the Japanese Imperial Army and on January 14, 1942, the town was again destroyed by fire. On April 19, 1945, the United States and Filipino forces liberated the town from Japanese occupation. The general headquarters of the Philippine Army and Constabulary under the Commonwealth regime was built and station in Calauag during and after the war from 1945 to 1946 against the possible remaining Japanese Armies.

Calauag experienced a big controversy due to a decade-long boundary dispute with the neighboring town of Santa Elena in the province of Camarines Norte, which resulted in a Supreme Court case, Presidential intervention, and the loss of a quarter of its land area. The disputed barangays were:

On October 14, 1991, the Provincial Government of Quezon and Municipal Government of Calauag ordered the demolition of a boundary marker installed by the DENR. In October 1995, then-President Fidel V. Ramos came to Calauag to meet with local officials to resolve the boundary dispute between the two provinces and surveyed the whole disputed area. Calauag retained its jurisdiction. However, the case was elevated to the Supreme Court. The Case of Province of Quezon vs. Province of Camarines Norte eventually ruled in favor of Camarines Norte and Calauag ceased its political jurisdiction on the said barangays.

Calauag is located on the north-eastern end of Tayabas Isthmus. The Daang Maharlika or Pan-Philippine Highway runs at the town after Lopez in Southbound and after Santa Elena at the Northbound or from Manila. At the north end of Quirino Highway, it meets Daang Maharlika in Barangay Tabugon. It also meets the north end of Guinayangan Provincial Road which also meets Daang Maharlika in Barangay Sumulong. It is bounded to the north-west by Calauag Bay, south-west by Lopez, to the east by Guinayangan, and to the north by Basiad Bay and Tinig Bay; it is separated from Alabat Island by a kilometer narrow straight.

Calauag is 227 kilometres (141 mi) southeast of Manila and 97 kilometres (60 mi) east from provincial capital Lucena.

Calauag is politically subdivided into 81 barangays, as indicated below. Each barangay consists of puroks and some have sitios.