Wales international Davies is set to face his old club on Sunday for the first time since moving from the Liberty Stadium to White Hart Lane in July.
The 21-year-old initially struggled to break into Tottenham's first team, but has started the club's last four Premier League matches.
And Swansea manager Monk feels there is much more to come from the youngster as he grows accustomed to his new environment.
"Ben's a great player for them and he's still developing for them," Monk is quoted as saying by the BBC.
"It took him a little time to settle, and I don't know the ins and outs of what he's been like in training, but I've seen some of the games that he's played recently and he's done very well.
"He's developing as a player and I'm sure Tottenham have yet to see the best of him but I'm sure they'll get to see that in future."
Swansea captured Gylfi Sigurdsson as part of a deal that saw Davies and goalkeeper Michel Vorm join Tottenham.
"The deal was done because we needed a player in midfield, and Gylfi has been great for us," Monk added.
"But it was not done with the thought that we'd get the better player. Ben will be a great player for Tottenham."
