The 2017–18 Eastern Counties Football League season (known as the 2017–18 Thurlow Nunn Eastern Counties Football League for sponsorship reasons) was the 75th in the history of Eastern Counties Football League, a football competition in England. It was also the last season to have a single division at Step 6. The constitution for Step 5 and Step 6 divisions for 2017–18 was announced on 26 May 2017, and the Eastern Counties divisions constitutions were ratified at the league's AGM on 17 June 2017.