Mr Key will attend a number of commemorative services on the Gallipoli Peninsula on April 24 and 25, including the dawn service, the New Zealand Service at Chunuk Bair and the Australian Service at Lone Pine.
Mr Key and Australian Prime Minister Abbott will jointly attend the Anzac Day services on April 25.
"We are delighted the Prince of Wales and Prince Harry will also be attending Gallipoli services in Turkey on the 24th and 25th of April," Mr Key said.
The Prime Minister's official delegation includes Veterans' Affairs Minister Craig Foss, Opposition Leader Andrew Little, Chief of Defence Force Lieutenant General Tim Keating and other senior Defence personnel, and RSA President Barry Clarke.
Also in the official party will be 25 youth ambassadors, highly decorated New Zealand veteran Brigadier Neville Reilly and historian Dr Chris Pugsley.
"Gallipoli is hugely significant for New Zealand, Australia and Turkey. It's where the Anzac relationship was cemented and it also a very important chapter in Turkey's history," said Mr Key.
"The Anzac spirit lives on in the way that New Zealand works collaboratively and respectfully with Australia, together with our Turkish hosts to hold the Anzac Day commemorations in Gallipoli every year.
"Turkey commits significant resources to ensuring these important commemorations are undertaken safely and respectfully, and we are grateful for their hospitality."
Throughout the week there will be a number of significant events culminating in Anzac Day services around New Zealand.