Bentley will miss Friday's home game against Toulouse Olympique and the visit of Hull KR seven days later.
The RFL's match review panel issued a two-game penalty notice after Bentley was sin-binned during Rhinos' 16-14 defeat at Castleford Tigers.
He was charged with a grade B reckless high tackle.
Bentley was banned for four matches following a red card for a high tackle on his debut against Warrington Wolves in February.
An original three-match suspension was increased after Bentley launched what a disciplinary tribunal felt was a "frivolous" appeal.
Fellow forward Zane Tetevano will also miss Rhinos' next two games after being suspended for a late tackle on the passer in Rhinos' draw with Huddersfield Giants last Thursday.
That is his second ban of the season and hooker Brad Dwyer has also been suspended twice.
In total, since their opening pre-season match, Rhinos have had 12 sin-binnings, one dismissal and three players charged over incidents which did not lead to a card during the game.
Toulouse will be without Maxime Puech for Friday's game after he received a one-match penalty notice for a grade B late hit on a passer against Hull KR.
Tigers' Joe Westerman was charged by the review panel with grade A dangerous contact against Leeds, but received a zero-game penalty notice.
Hull captain Luke Gale has been handed his second ban of the season after being charged with a grade B trip, which the panel deemed 'reactionary or reckless' in Monday's win over Warrington Wolves.
He was suspended for five matches after being sent-off against St Helens in Super League round two.
Salford Red Devils' former Rhinos captain Kallum Watkins received a zero-match penalty notice after being charged with a grade A late hit.
St Helens' Curtis Sironen will miss two games, including Friday's visit to Castleford, for a grade B late hit.
Cautions were issued to Wakefield Trinity's Kelepi Tanginoa and Catalans Dragons' Alrix Da Costa (both late hit on passer) and Salford's King Vuniyayawa (other contrary behaviour).