The "vast majority" of coaches break on-court coaching rules and allowing it would help "attract new people" to tennis, says Serena Williams' coach Patrick Mouratoglou.
On-court coaching is banned in Grand Slams but is allowed in WTA events.
Mouratoglou admitted coaching Williams during her dramatic US Open final loss last month with Williams later docked a game for calling the umpire a "thief".
The Frenchman says on-court coaching "adds to the drama" of the sport.
In a lengthy statement, Mouratoglou also said that banning coaching "almost makes it look as if it had to be hidden, or as if it was shameful".
"It is time tennis leaders amend the status of coaching," he added. "If we don't get people involved, then tennis is only ever going to be followed by pure tennis lovers.
"We need to show the viewers the personalities of the people they are watching.
"We have to keep those elements that make tennis so special but we also have to appeal to a modern, younger audience."
Williams received a code violation during the US Open final defeat by Naomi Osaka when Mouratoglou made a hand gesture to the American but she denied she received coaching.
"It's a very basic truth that the vast majority of tennis coaches are actually coaching on court, despite the rules," Mouratoglou said.
"Look how many times players looks towards their boxes during a match. Some do it after every point."