Alicia, officially the Municipality of Alicia (Ilocano: Ili ti Alicia; Tagalog: Bayan ng Alicia; formerly known as Angadanan Viejo), is a municipality in the province of Isabela, Philippines. According to the 2024 census, it has a population of 74,699 people.

It is known for the Pagay Festival Balitok Ti Alicia and its famous historical landmark, the Our Lady of Atocha Church completed and inaugurated in 1849 which was officially declared by the Philippine Department of Tourism as a national religious tourist destination in the Philippines.

When President Elpidio Quirino signed Executive Order No. 268 on 28 September 1949, Old Angadanan was formally created and renamed Alicia after his late wife, Doña Alicia Syquía Quirino. Along with three of their children (except Tomás, a soldier, and Victoria, who later became First Lady for her father), Doña Alicia was one of many civilians massacred by Japanese occupiers on 9 February 1945 during the Battle of Manila.

Alicia was the second site of the town of Angadanan, which was initially founded in the mid-18th century as a settlement in present-day Nueva Vizcaya, between the towns of Bagabag and Bayombong. The town took its name from the nearby Angaranan Creek. In 1776, the Spaniards decided to move the settlement further north to Alicia's present location along the Ganano river, a tributary of the Cagayan River. In the 19th century, the Spaniards decided to move Angadanan again 6 km (3.7 mi) further east along the Cagayan River to facilitate better transportation links and to secure the town from repeated raids by the Igorots and Gaddangs. The second site was subsequently known as Angadanan Viejo (Old Angadanan) to distinguish it from its third site called Angadanan Nuevo (New Angadanan), to which the former was a part of until Angadanan Viejo was converted into the separate municipality of Alicia in 1949. Part of the reason for the separation was that Alicia lay alongside the national highway network, which led to a more flourishing economy than its mother settlement.

Both the second and third Angadanans were part of the Cagayan Valley province. The entire Cagayan Valley was one large province which the Spaniards called La Provincia del Valle de Cagayan, but divided into two new provinces in 1839 by the Spanish conquistadors. One retained the old name Cagayan which comprised all towns from Aparri to Tumauini; while a new province of Nueva Vizcaya was created composed of all towns from Ilagan to the Caraballo del Sur.

A Royal Decree was created on 1 May 1856 creating Isabela de Luzon to distinguish it from other Isabelas in the Philippines, to which both Angadanans were added. It was placed under the jurisdiction of a governor with the capital seat at Ilagan, where it remains at the present.

Alicia has a total land area of 15,410 hectares. 71% of the total land area is an agricultural land which makes Alicia primarily an agricultural municipality best suited for the intensive production of rice and corn. Farming is its major livelihood and rice its major product and resource.

The municipality is located in an area of predominantly flat and fertile land in the Cagayan Valley that is surrounded by the Caraballo Mountains to the south, the Great Sierra Madre to the east, and the Cordillera Mountain Range to the west. It is the largest rice producer in the entire Cagayan Valley and has the largest irrigated rice field in the whole Region II of the Philippines.