The 2014–15 Pro12 (also known as the Guinness Pro12 for sponsorship reasons) was the 14th season of the professional rugby union competition originally known as the Celtic League, and the fifth with its current four-country format.

[1][2] Leinster were the defending champions having beaten Glasgow Warriors in the previous season's playoff final, to become the first team in the league to successfully retain the trophy.

[3] Leinster were unable to defend their title as they failed to qualify for the end-of-season playoffs for the top four teams after the regular season.

Glasgow Warriors finished the regular season on top of the table, and were crowned champions for the first time, beating second seeded team Munster 31–13 in the final.

[4][5][6] Thus, the Warriors became the first Scottish team to win a professional trophy, beating Edinburgh's appearance in the final of the 2014–15 European Rugby Challenge Cup.

The Guinness PRO12 Trophy is a 60 cm tall piece handmade made by silversmith Thomas Lyte from 8.3 kg of sterling silver, with league branding highlighted in gold plate.

[11] Leinster came into the competition without the services of long serving player Brian O'Driscoll, who retired at the end of the 2013–14 season, for the first time.

[13] Irish international Jamie Heaslip was announced as the side's new captain in August 2014, with Rob Kearney and Seán O'Brien serving as his vice-captains.

In June 2014, David Humphreys left his post as the province's Director of Rugby, joining English Premiership side Gloucester.

[19] In October 2014, Kiss returned to his position with the Ireland team, with Neil Doak taking the role of head coach.

[24][25] Ahead of the 2014–15 season, Edinburgh lost a number of experienced players, including Geoff Cross, Nick De Luca, Greig Laidlaw and Ross Rennie.

[26] Edinburgh's home ground of Murrayfield was resurfaced by the time the new season began, following an infestation of nematodes, a type of parasitic worm.

Scarlets were also without the services of one of the previous season's joint captains Jonathan Davies, who departed to join French side Clermont Auvergne.