Aernout van Lennep (23 February 1898 – 17 December 1974) was a Dutch horse rider. He competed in eventing at the 1932 Summer Olympics and won a team silver medal, finishing ninth individually.^[1]

Van Lennep was a career artillery officer, and won the Dutch military championships in 1931. He was a prisoner of war in Germany during World War II, and later became a lieutenant colonel in the 1950s.^[1]