Spencer Horsey de Horsey (1790 – 20 May 1860), previously known as Spencer Horsey Kilderbee until 1832, was a British Tory politician. He served in the House of Commons from 1829 to 1841.

The son of Rev. Samuel Kilderbee, DD, rector of Campsey Ash, and his wife Caroline, sole daughter and heiress of Samuel Horsey of Bury St Edmunds, he married Lady Louisa Rous, the youngest daughter of John Rous, 1st Earl of Stradbroke, in Wangford in 1824. They had three children: Algernon Frederick Rous de Horsey, William Henry Beaumont de Horsey, and Adeline Louisa Maria de Horsey. Spencer passed away at his residence in Cowes but also maintained homes at 8 Upper Grosvenor Street, Mayfair (from 1830 to 1858), and in Great Glemham, Suffolk.

Elected as the Member of Parliament (MP) for Aldeburgh in Suffolk during a by-election in May 1829, he retained the position until the 1830 general election, after which he represented Orford, also in Suffolk. He was re-elected in 1831 and served until the 1832 general election when the borough lost its representation due to the Reform Act. In April 1832, he adopted the name Spencer Horsey de Horsey by Royal Licence, taking his mother's maiden name.

After a five-year hiatus, he returned to Parliament as the MP for Newcastle-under-Lyme in Staffordshire following the 1837 general election. He remained in this role until the 1841 general election, after which he chose not to run again.