Jacob van Lennep (24 March 1802 - 25 August 1868) was a Dutch poet and novelist.

He was born on the Amsterdam, where his father, David Jacob van Lennep (1774-1853), a scholar and poet, was professor of eloquence and the classical languages in the Athenaeum. Lennep took the degree of doctor of laws at Leiden, and then settled as an advocate in Amsterdam.

His first poetical efforts had been translations from Byron, of whom he was an ardent admirer, and in 1826 he published a collection of original Academische Idyllen, which had some success. He first attained genuine popularity by the Nederlandsche Legenden (2 vols., 1828) which reproduced, after the manner of Sir Walter Scott, some of the more stirring incidents in the early history of his fatherland. His fame was further raised by his patriotic songs at the time of the Belgian revolt , and by his comedies Het Dorp aan de Grenzen (1830) and Het Dorp over de Grenzen (1831), which also had reference to the political events of 1830.

In 1833 he broke new ground with the publication of De Pleegzoon (The Adopted Son), the first of a series of historical romances in prose, which acquired for him in Holland a position somewhat analogous to that of Sir Walter Scott in Great Britain. The series included De Roos van Dekama (2 vols., 1836), Onze Voorouders (5 vols., 1838). De Lotgcvallen van Ferdinand Huyck (2 vols, 1840), Elizabeth Musch (3 vols., 1850), and De Lot gevallen van Klaasje Zevensler (5 vols., 1865), several of which have been translated into German and French, and two - The Rose of Dekama (1847) and The Adopted Son (New York, 1847) into English.

His Dutch history for young people (Voornaamsle Geschiedenissen van Noord-Nederland aan inijne Kind em verhaald, 4 vols, 1845) is attractively written. Apart from the two comedies already mentioned, Lennep was an indefatigable journalist and literary critic, the author of numerous dramatic pieces, and of an excellent edition of Vondel's works. For some years Lennep held a judicial appointment, and from 1853 to 1856 he was a member of the second chamber, in which he voted with the conservative party. He died at Oosterbeek near Arnheim in 1868.

There is a collective edition of his Poetische Werken (13 vols., 1859-1872), and also of his Romantische Werken (23 vols., 1855 r872). See also a bibliography by P. Knoll (1869); and Jan ten Brink , Geschiedenis der Noord-Nederlandsche Letteren in de XIX Eezsw ~No. iii.).