A military transport aircraft carrying their coffins touched down at the Royal Air Force (RAF) base at Brize Norton at 11:00 am (1000 GMT) ahead of a 45-minute repatriation ceremony in front of relatives.
The five dead included the first British woman to be killed in the line of duty in Iraq, 32-year-old RAF Flight Lieutenant Sarah Mulvihill.
Her husband Lee, a sergeant in the RAF, described her as "my best friend and my most beloved wife" and said they were both proud to serve in the British armed forces.
"Her loss has greatly affected and impacted on more people than anyone can comprehend," he said in a statement released after the military service at the Oxfordshire, southern England, airfield.
RAF Wing Commander John Coxen, 46, army Captain David Dobson, 27, naval Lieutenant Commander Darren Chapman, 40, and Marine Paul Collins, 21, also died in the crash on May 7.
The helicopter is believed to have been shot down by insurgents. An investigation is currently under way into the exact cause.
The fatalities brought the British military death toll in Iraq since the March 2003 US-led invasion to 109.
Two more British soldiers died last weekend when a roadside bomb exploded while they were on routine patrol, taking the death toll up to 111.
The coffins, draped in the Union Jack flag, were flown back from the Gulf following a sunset ceremony in Basra attended by Britain's new Defence Secretary Des Browne.
The Royal Navy's deputy commander of Joint Helicopter Command, Commodore Tony Johnstone-Burt, said after the ceremony: "They died doing their duty. They were all totally and selflessly committed to their task."
He added: "I am confident that their sacrifice in the line of duty has stiffened the resolve of all those on operations, regardless of their rank or rate, and made them even more determined to live up to their memory and finish the job that they've started. They will not be forgotten."