The 21-year-old Ryan made his senior debut for the province away to the Dragons at the beginning of December.
He is rewarded with his home debut in a back row which includes in-form duo Stephen Keogh and Kevin McLaughlin.
Bernard Jackman will captain the side, having been named in a powerful front row alongside fellow Ireland international Mike Ross and South Africa's CJ van der Linde.
O'Malley, meanwhile, continues his centre partnership with Fergus McFadden, while Paul O'Donohoe comes in at scrum half alongside Australian out-half Shaun Berne.
Speaking ahead of the game against Glasgow, Jackman said that the squad is determined to maintain their standing at the top of the Magners League.
"The win over Cardiff was satisfying because everyone stepped up to the plate. It was a real team performance and some of the younger guys really put it up to them which does give you a good lift," he said.
"The dressing room afterwards was a pretty happy place to be in and it was up there with some of our big Heineken Cup wins over the years.
"From a forwards perspective our set piece went well and this week we know that we will need to be as sharp, if not sharper again.
"We're exactly where we want to be at the top of the Magners League and we've got to push on from here.
"Glasgow are a side who always put it up to you. Scottish sides sometimes don't get the respect that they deserve yet themselves and Edinburgh are right up on the top end of the Magners League table, but we know all about the threats that they can pose."
The Carlow-born hooker added: "It is a huge honour to be asked to lead the team out again, but the mindset from our point of view is that we must back up our recent wins and everyone who is selected has an opportunity to stake a claim on a Leinster shirt."
Over 14,000 tickets have now been sold for Thursday's tie and tickets are still available online and from the usual outlets in Donnybrook.
Ticketmaster outlets nationwide also have tickets on sale and will be selling tickets outside the RDS from 5pm on Thursday. Please note that all tickets issued for this original fixture date of January 8 are still valid.
LEINSTER (v Glasgow Warriors): Girvan Dempsey; Simon Keogh, Eoin O'Malley, Fergus McFadden, Isa Nacewa; Shaun Berne, Paul O'Donohoe; CJ van der Linde, Bernard Jackman (capt), Mike Ross, Devin Toner, Malcolm O'Kelly, Kevin McLaughlin, Paul Ryan, Stephen Keogh.
Replacements: Richardt Strauss, Stan Wright, Trevor Hogan, Eoin Sheriff, Chris Keane, Ian Madigan, Michael Keating.