Binyamin Needham, 19, had only been serving in the territory for two days when he was killed in action, according to a statement released by the IDF. He had celebrated his birthday just two weeks before his death.
Israeli newspaper Haaretz said the soldier, who had dual nationality, was born in Edgware, north London and moved to Israel at the age of eight. He was the youngest of five children.
He is understood to be the second British national to have been killed while serving with the IDF since the October 7 attacks. The first was 20-year-old Nathanel Young.
Needham was one of three soldiers who died in combat operations in Gaza on Sunday, the IDF said.
His sister Orli Ferris told Haaretz: “He was such a wonderful, wonderful brother and we loved him with all our hearts and we always will. He will be missed by all of us and so many others, but we will always make sure we remember him in our hearts.
“Nothing will be the same now, but we are all very proud of what he did and he was also proud of what he was doing. He had just finished his apprenticeship and was doing his professional training. We don't know the exact details of what happened but he was only in Gaza for two days. He went in on Friday and died Sunday."
Ms Ferris added: “We are so so sad and my parents are devastated, we can't make any sense of it and we are heartbroken. We shall honour him and keep his memory alive. He was a wonderful boy and everyone who knew him said the same.
“He died with a pure soul and he died protecting his country. He would go back to London every year or so to see his siblings who live there.”
Neriya Shaer and Ben Zussman were named as the other IDF soldiers who died while serving in Gaza on Sunday.
The IDF said that 75 soldiers have been killed since the beginning of the military operation in the enclave last month.
Israel began its bombardment of the Gaza Strip in response to a brutal terrorist attack by Hamas militants on October 7 which killed more than 1,200 people in southern Israel.
More than 15,500 Gazans have been killed in the territory since the IDF began their operation, according to the Hamas-run health ministry.