The decision follows a successful bid by the Rugby Football Union in the tender process, which was open to the six countries competing in the successor to the Heineken Cup.
It will be the fifth time Twickenham has hosted European club rugby's annual showpiece with competition now entering a 20th year.
"The RFU's bid will guarantee the best possible financial return to the clubs," a statement released by EPCR read.
London will also provide the setting for the final of the European Rugby Challenge Cup with Twickenham Stoop, home to Harlequins, staging the event on May 1.
"The RFU's bid was extremely strong," EPCR director and executive committee member Bruce Craig said.
"The fact that we're going to London for the 2015 finals is hugely positive for European club rugby."
Tickets for the two finals go on public sale on Monday.
- Sports & Recreation
- Rugby Football Union
- Heineken Cup
- Twickenham Stoop