Colonel Evan Henry Llewellyn (25 February 1847 – 27 February 1914) was a British Army officer and a Conservative politician who sat in the House of Commons between 1885 and 1906.
Llewellyn was the fourth son of Llewellyn Llewellyn of Buckland Filleigh, North Devon. He was educated at Rugby School. He was a J.P. and Deputy Lieutenant of Somerset. He served in the British Army, where he was an officer in the 4th (Militia) battalion of the Somersetshire Light Infantry. Following the outbreak of the Second Boer War in late 1899, he volunteered for active service when the battalion was embodied that December, and left Southampton for South Africa on the in early March 1900. He was later the commander of the 2nd (Central African) Battalion, King's African Rifles.
In the 1885 general election, Llewellyn was elected as Member of Parliament (MP) for North Somerset and held the seat until the 1892 general election. He was re-elected for the seat in the 1895 general election and held it until the 1906 general election.
Llewellyn lived at Langford Court, Somerset. His son Hoel also served with distinction in the Second Boer War. He is the great-great-grandfather of David Cameron, who was Prime Minister of the United Kingdom from 2010 to 2016.