The 1977–78 Southern Football League season was the 75th in the history of the league, an English football competition.
Bath City won the championship, winning their second Southern League title, whilst Witney Town, Margate, Bridgend Town and Dorchester Town were all promoted to the Premier Division, the former two as champions.
Romford folded at the end of the season.
Champions Bath City participated in the vote, but finished bottom.
NPL club Wigan Athletic were elected to the League after beating Southport in a second round of voting.