Captain Horatio Hornblower is a 1951 British naval swashbuckling war film in Technicolor from Warner Bros., produced by Gerry Mitchell, directed by Raoul Walsh, that stars Gregory Peck, Virginia Mayo, Robert Beatty and Terence Morgan.

The film is based on three of C. S. Forester's Horatio Hornblower novels: The Happy Return (1937), A Ship of the Line (1938), and Flying Colours (1938).

In 1807, during the Napoleonic Wars, Royal Navy Captain Horatio Hornblower is given command of the 38-gun frigate HMS Lydia and tasked with a secret mission to Central America: he is to provide arms and support to a local warlord, Don Julian Alvarado, who has organized a rebellion against the colonial authorities of Spain, an ally of Britain's enemy France.

Two passengers board the Lydia (over Hornblower's strenuous objections): Lady Barbara Wellesley and her maid, fleeing a yellow fever epidemic.

Hornblower's French-built ship is subsequently mistaken for a friendly vessel by a small French brig, which flies the enemy's recognition signal for the day.

As the rest of the British squadron arrives to complete the job, Hornblower, his first officer Bush, and Sutherland coxswain Quist are sentenced to hang for piracy in the center of Paris.

They manage to escape and make their way to the port of Nantes, where they crash a party and commandeer the uniforms of three Dutch customs officers so they can board the Witch of Endor, a captured British ship.

They overpower the skeleton crew, free a working party of British prisoners of war to man her and sail to England.

Warner Bros. acquired the film rights to the first three Hornblower novels – The Happy Return, A Ship of the Line, and Flying Colours – as a star vehicle for Errol Flynn[2] when they were first published.

For reasons that may have included the financial failure of the 1948 Adventures of Don Juan, the growing difficulties of working with the actor, and/or his advancing age,[3] Flynn was not cast.

[5] The film was shot at studios inside the United Kingdom, on Mermaid Street in Rye, East Sussex, at HMS Victory and also on location in France.

To save costs, the Hispaniola set from the 1950 Disney film adaptation of Treasure Island was reused as the frigate HMS Lydia.

The premiere was in aid of King George's Fund for Sailors and the "Foudroyant" appeal (the presently restored frigate renamed HMS Trincomalee afloat in the Historic Quay, Hartlepool, UK).

[16] Peck and Mayo recreated their roles on a one-hour Lux Radio Theater program broadcast on 21 January 1952, which is included as an audio-only feature in the film's DVD release.