Ten Hag is also among a handful of names linked to the top job at Manchester United as interim manager Ralf Rangnick's tenure is set to conclude at the end of the campaign. Sources have told ESPN that Ten Hag has held talks over the role at Old Trafford.
Guardiola joined City in 2016 and has a contract until the end of next season. He said in January he might make a decision on his future this summer.
"Could Erik ten Hag be here at City? Definitely. I think he could be the one," Guardiola said. "For the way he approaches the game, definitely."
Guardiola worked with Ten Hag at Bundesliga club Bayern Munich for two seasons when Ten Hag was in charge of the second team.
The 52-year-old was appointed by Ajax during the 2017-18 campaign and led them to the Dutch league title in 2019 and 2021, as well as the Champions League semi-finals in 2019.
"For his qualities, just take a look at his Ajax team in the last years," Guardiola said.
"It is a joy to watch and in many games, not just the year they got to the Champions League semi-final, but with little details they would have reached that final."
Ten Hag told German TV channel Sport1 he could not rule out leaving Ajax this summer.
"My focus is currently only on Ajax," Ten Hag said. "But in football, you never know."
Asked to confirm if he had spoken to United, he said: "Everyone knows each other in the industry. There are always talks with representatives from other clubs -- that's normal."