2018–19 Spartan South Midlands Football League

The 2018–19 Spartan South Midlands Football League season is the 22nd in the history of Spartan South Midlands Football League, a football competition in England.

The provisional club allocations for steps 5 and 6 were announced by the FA on 25 May. The constitution is subject to ratification by the league at its AGM on 23 June.

Premier Division
At the end of the 2017–18 season, the following teams left the division:
 * Promoted to Step 4
 * Berkhamsted, to Southern League East
 * Welwyn Garden City, Southern League East
 * Transferred within Step 5
 * Hoddesdon Town, to the Essex Senior League
 * Holmer Green, to the Hellenic League
 * St Margaretsbury, to the Essex Senior League

The remaining 16 teams, together with the following, form the Premier Division for season 2018–19:
 * Promoted from Step 6
 * Baldock Town, from Division One
 * Potton United, from United Counties League Division One
 * Transferred within Step 5
 * North Greenford United, from the Combined Counties League
 * Relegated from Step 4
 * Arlesey Town, from Southern League East

Division One
At the end of season 2017–18, the following teams left the division: The remaining 17 teams, together with the following, form Division One for 2018–19:
 * Promoted to Step 5
 * Baldock Town, to the Premier Division
 * Southall, to the Premier Division
 * Relegated to Step 7
 * St Neots Town Reserves
 * Promoted from Step 7
 * Amersham Town, from Division Two
 * Park View, from Division Two
 * Transferred within Step 6
 * Buckingham Town, from the United Counties League