The first American-British Western filmed in Spain was The Sheriff of Fractured Jaw, directed by Raoul Walsh. It was followed by Savage Guns, a British-Spanish Western, again filmed in Spain. It marked the beginning of Spain as a suitable film-shooting location for any type of European Western. In 1961, an Italian company coproduced the French Taste of Violence, with a Mexican Revolution theme. In 1963, three non-comedy Italo-Spanish Westerns were produced: Gunfight at Red Sands, Implacable Three, and Gunfight at High Noon.

In 1965, Bruno Bozzetto released his traditionally animated feature film West and Soda, a Western parody with a marked spaghetti Western-theme; despite having been released a year after Sergio Leone's seminal spaghetti Western, A Fistful of Dollars, development of West and Soda actually began a year earlier than Fistful's, and lasted longer, mainly because of the use of more time-demanding animation over regular acting. For this reason, Bozzetto claims to have invented the spaghetti Western genre.

Because there is no real consensus about where to draw the exact line between spaghetti Westerns and other Eurowesterns (or other Westerns in general), it cannot be said which film is definitively the first spaghetti Western. However, 1964 saw the breakthrough of this genre, with more than twenty productions or coproductions from Italian companies, and more than half a dozen Westerns by Spanish or Spanish-American companies. Furthermore, by far the most commercially successful of this lot was Sergio Leone's A Fistful of Dollars. It was the innovations in cinematic style, music, acting and story of Leone's first Western that decided that spaghetti Westerns became a distinct subgenre and not just a number of films looking like American Westerns.