The Spanish National Organization of the Blind (Spanish: Organización Nacional de Ciegos Españoles), commonly known as the ONCE (Spanish pronunciation: [ˈonθe], as in the Spanish word for the number 11), is a Spanish foundation founded on December 13, 1938, to raise funds to provide services for the blind and people with serious visual impairment.

Although it is overseen by a board of patrons made up of representatives from various Spanish ministries, it does enjoy a certain amount of freedom of movement in the day-to-day running of its activities, and its general council is democratically elected from among its members.

As of September 2013, membership of the organization was 71,460 people, of whom 40% were over the age of 65.

Between them, the three pillars of the ONCE—the Directorate-General, the Foundation and CEOSA, ONCE's business corporation—employ over 136,000 staff, of whom 88.5% are people with disabilities.

In September 2013, coinciding with the organization's 75th anniversary, the ONCE was awarded Spain's Premio Príncipe de Asturias for Concord.

From 1989 to 2003, ONCE sponsored one of Spain's leading cycling teams.