In a statement, Trudeau said Wednesday morning's crash claimed the lives of all 176 people on board, including 63 Canad, Efe news reported.
"On behalf of the Government of Canada, Sophie (Trudeau's wife) and I offer our deepest condolences to those who have lost family, friends and loved ones in this tragedy," he wrote.
The prime minister also said Ottawa will make every effort to ensure that the crash of the Boeing 737-800 jet is thoroughly investigated.
Despite heightened tensions between the United States and Iran following the Jan. 3 assassination of a prominent Iranian general in a US airstrike in Baghdad and retaliatory missile attacks Wednesday by Tehran on military bases in Iraq housing American forces, Chicago-based Boeing released a brief statement offering to help with the investigation.
"This is a tragic event and our heartfelt thoughts are with the crew, passengers and their families. We are in contact with our airline customer and stand by them in this difficult time. We are ready to assist in any way needed," the company said.
The 737-800 is the predecessor to Boeing's 737 MAX, a model that remains grounded worldwide after a pair of deadly crashes.
Iranian authorities, however, already have said they will not provide the plane's black boxes to Boeing or the United States and that the crash will be jointly investigated by Iran and Ukraine.
Prior to Trudeau's statement, Canadian Foreign Minister Francois-Philippe Champagne said on Twitter that "many Canad" were among the 176 people - 167 passengers and nine crew members - killed in the crash of UIA Flight 752 from Tehran's Imam Khomeini International Airport to Kiev.
Ukrainian authorities said that, in addition to the 63 Canad on board, 82 Iran, 11 Ukrain (two passengers and nine crew members), 10 Swedes, four Afghans, three Germans and three Britons were killed in the crash.
Toronto-based daily The Globe and Mail said many of the Canad who died were Iranian-Canadian students returning to school at the end of their winter break. UIA's fares are among the lowest in the market for passengers travelling between Toronto, Canada's largest city, and Tehran.
Flight 752 crashed shortly after takeoff for reasons that remain unknown.
Although Ukrainian authorities initially blamed engine failure for the crash, Kiev later deleted that statement and said the cause of the air disaster is under investigation.
( With inputs from IANS )