The Blues travelled to Ukraine with a commanding 3-0 lead from the first leg in London a week ago and any faint hopes that Alyaksandr Khatskevich's side had of clawing their way back into the tie were extinguished by Giroud's fifth-minute opener.
The Frenchman added a second shortly after the half-hour mark before Marcos Alonso tapped in a third just before the interval.
Giroud completed his hat-trick in the 59th minute and Callum Hudson-Odoi added a fifth 12 minutes from time as Maurizio Sarri's side made it four wins from their last five games in all competitions.
Fresh from his call-up to the France squad earlier on Thursday, Giroud got Chelsea up and running when Willian's corner was deflected into his path six yards out and the 32-year-old had the simple task of steering home.
Ruben Loftus-Cheek was denied by a fine Denys Boyko save soon after before Giroud grabbed his second in the 33rd minute by applying a superb finishing touch to Alonso's cross from 12 yards.
Provider then turned scorer on the stroke of half-time when Alonso prodded in from close-range after smart play down the right by Hudson-Odoi.
Serhiy Sydorchuk was denied by Kepa Arrizabalaga and the post in quick succession after the restart before Giroud brought up his hat-trick just before the hour with a neat header from Willian's free-kick.
Not long after Alonso crashed a free-kick against the crossbar, the impressive Hudson-Odoi sealed a memorable away day by collecting Giroud's pass and clipping past Boyko.
What does it mean? Sarri's struggles consigned to memory
A few weeks ago it was not inconceivable that Sarri would not even be in charge for this tie, but the Italian has weathered the storm – at least for now.
He came out of the Kepa fiasco in the EFL Cup final with his reputation arguably enhanced, has now comfortably steered his side through a potentially tricky Europa League tie and also overseen an upturn in their Premier League form. A great few weeks for the former Napoli boss.
Giroud forgets domestic woes
The World Cup winner has scored just once in the Premier League this season, but he is certainly enjoying himself in the Europa League. His perfect hat-trick puts him out on his own as the top scorer in this season's competition with nine goals.
Sydorchuk fluffs his lines
It hardly mattered to the final scoreline, but Dynamo's captain had two glorious chances to at least give the club's fans something to cheer. They both came in the same passage of play, but he was denied by Kepa and then the post when it looked easier to score.
Key Opta Facts:
- Chelsea's 8-0 aggregate win over Dynamo Kyiv is their second biggest European victory over two legs, the other being a 21-0 aggregate win over Jeunesse Hautcharage in the first round of the Cup Winners' Cup in 1971-72.
- It took Dynamo Kiev 140 minutes to direct a shot on target against Chelsea in the Europa League this season, managing none in the first leg and their first in 49 minutes in the second leg.
- Olivier Giroud has netted nine goals in European competition for Chelsea this season, the most for the club in a single season since Fernando Torres in 2012-13 (9).
- Courtesy of his left foot, right foot and headed goals, Olivier Giroud scored the first 'perfect' hat-trick in any competition for Chelsea since Didier Drogba in May 2010 in the Premier League against Wigan Athletic.
Chelsea return to Premier League action on Sunday with a trip to Everton, while Dynamo travel to Olimpik Donetsk on the same day in the Ukrainian Premier League.