It meant De Bruyne matched Henry's total of 20 for Arsenal, which he set in 2002/03.
He is the first player in Premier League history to provide at least 15 assists in three different campaigns, after his tallies of 16 in 2017/18 and 18 in 2016/17.
"It's obviously a nice achievement but I only do half the job,” De Bruyne told City's official website.
"I’m very grateful to my team-mates for the way they finish off the chances. Without them I wouldn’t have got that many assists."
It is also the second time De Bruyne has claimed the accolade, having captured the inaugural award, presented by Cadbury, in 2017/18.