The former 10-time world title holder over six different weight classes believes Khan has the makings of a world champion and backs the Briton to overtake the likes of Floyd Mayweather Jnr and Manny Pacquiao as the world's best pound-for-pound fighter.
De La Hoya said: "Amir's definitely up there in pound-for-pound terms. You can make that argument for him to become the best fighter in the world.
"We know Floyd Mayweather and Manny Pacquiao are on top at the moment, but Amir is right on their backs.
"With time, he can catch them. He's a young fighter and he's learning at a rapid pace.
"In every single fight, we have seen him get better. He can become the best."
Khan is currently in America gearing up for a fight against Lamont Peterson this Saturday and de La Hoya, who is promoting the fight, has warned the 24-year-old that he could face a tough outing in Washington, but still expected him to win.
"Peterson is very dangerous and fighting in his home town will be an extra motivation for him," added De La Hoya.
"Amir's the best out there at 140 pounds. He fought and beat Marcos Maidana who everybody thought would knock Amir out.
"But Amir showed he is the best in the division. He has a tremendous chin and heart to prove he is the best at 140."