De Blasio, a Democrat, wanted to ban the horses from Manhattan's streets and Central Park during his first week in office.
In a Google Hangout video chat on Friday, the mayor said he now expects the City Council to ban the practice by year's end.
De Blasio says he believes "a human society doesn't do that to animals."
But carriage-horse operators and allies - including actor Liam Neeson - have loudly opposed the mayor's plan.
The council has not yet introduced the legislation.
De Blasio's stop at Google's Manhattan office to chat with voters comes as part of his victory lap marking his first 100 days in office.