Alca

Alca may refer to:
 * Advanced Light Combat Aircraft; see Aero L-159 Alca
 * Alca, a genus of birds
 * Apostolic Lutheran Church of America
 * The Free Trade Area of the Americas, known as Área de Libre Comercio de las Américas in Spanish, and Área de Livre Comércio das Américas in Portuguese
 * The Professional Landcare Network, previously known as the Associated Landscape Contractors of America