World Rugby announced on Wednesday tackling height will be lowered to below the waist or the base of the sternum from the chest in the amateur game from July 1.
The change had been trialled in leagues across the globe in an attempt to improve player safety.
"I welcome the adoption of a lower tackle height into community law," World Rugby chairman Brett Robinson said.
"I would like to thank all the unions and academics and most importantly players and referees who took part in the trials that have helped us to reach this point.
"The trials from around the world show that this is the right thing to do to make our game safer and more enjoyable for community players who are the lifeblood of our sport," he added.
The tackle height reduction law variation will also be trialled at this year's world under-20s championship held between June 27 and July 18 in Georgia.