Rear-Admiral Sir Samuel John Brooke Pechell, 3rd Baronet CB, KCH, FRS (1 September 1785 – 3 November 1849) was a prominent British Royal Navy officer of the early nineteenth century.

In January 1806, Pechell joined his uncle's flagship HMS Foudroyant and was present at the defeat of the French squadron under Admiral Charles Linois at the action of 13 March 1806.

In June 1808, he was promoted to post captain and took command of the frigate HMS Cleopatra, in which he joined the squadron being assembled at Barbados for operations against the French islands of Martinique and Guadeloupe.

Pechell's dispositions were so good that Topaze was soon unable to respond, and the arrival of two other Royal Navy ships allowed him to bring his prize out of the bay successfully.

[1] In 1823 he returned to active service aboard the frigate HMS Sibylle and operated off Algiers and the Peloponnese, following the surge in piracy caused by the Greek War of Independence.

As a serving captain, Pechell had copied and then adapted the system used by Philip Broke, writing a pamphlet on the topic entitled "Observations upon the Defective Equipment of Ships' Guns".

He died childless at his home in Berkeley Square, London in November 1849, and was survived by his wife and younger brother, who became the fourth Pechell Baronet.