The 20-year-old joined the club as a teenager from Chelsea in 2017 and has gone on to play three times for the first team. Having played twice during the 2018-19 campaign, Ramsay was called back into action earlier this month, playing the full 90 minutes in Saints’ 9-0 loss at Manchester United.
Saints academy director Matt Hale said: “It’s been great to see Kayne feature regularly in recent weeks as part of the first-team squad. Kayne is developing and maturing all the time, learning more and more about the senior playing philosophy. It is great to see Kayne commit to the club and continue his progress. We have great confidence he will continue to grow and be a part of the club’s future.”
Aside from his appearance at Old Trafford, Ramsay has also been an unused substitute for eight further senior Saints matches this season.