Rinder was born into a Jewish family in London on 31 May 1978. His maternal great-grandfather left Talsi, Latvia – then within the Russian Empire – after the 1905 Russian Revolution and joined the British Army in World War I. The grandson of a Holocaust survivor, Rinder's maternal family roots extend back to Piotrków Trybunalski, Poland. After the Nazi invasion of Poland at the start of World War II, his maternal grandfather, Moses (also known as Maurice) and his family were sent to a ghetto, where Maurice worked in a local glass factory. With most of the family sent to Treblinka extermination camp, Maurice as a worker was then moved to a concentration camp in Schlieben, Germany, to work in a tank munitions factory.