John Sydenham (25 September 1807– 1 December 1846) was an English antiquary. In 1829 he became editor of the Dorset County Chronicle. In 1840 Sydenham left the Dorset Chronicle and became editor of The West Kent Guardian, a Greenwich paper. In January 1846 he returned to Poole and started The Poole and Dorsetshire Herald, of which he was editor and part-proprietor. He was one of the early members of the British Archæological Association.