O'Malley has featured in 16 games so far this season, including making his Heineken Cup debut in the cauldron of Stade Marcel Michelin, and was recently awarded with his first O2 Ireland Wolfhounds caps against Scotland and England.
The former 22-year-old centre, who made his Leinster debut in the 2009/10 season, has played 23 times in total for his home province.
Ireland flanker Ruddock, meanwhile, has agreed his first full-time deal with the province and to date has featured in 13 games this season.
Educated in Millfield School, the Dublin-born 20-year-old joined Leinster in the 2009/10 campaign - the same season he captained the Ireland Under-20s to the Six Nations title.
Commenting on the deals, Leinster head coach Joe Schmidt said: "We are delighted that two more products of the Leinster underage and Academy systems have signed new deals.
"Both Eoin and Rhys have made an impact with their performances in the Magners League and Heineken Cup so far this season.
"The role of the Academy is crucial in the development of our young players and both Rhys and Eoin, with their work ethic and talent, exemplify the Academy products we are fortunate enough to have here in Leinster."