What is Margaret Thatcher's net worth? Margaret Thatcher's net worth is $10 million dollars. Born in Grantham, Lincolnshire, United Kingdom, Margaret Thatcher, also known as Margaret Hilda Roberts, attended Kesteven and Grantham Girls' School on scholarship, and then went on to graduate from Somerville College, Oxford with a Bachelor of Science degree in Chemistry. While working for BX Plastics in Essex, she became very involved with the Conservative Party. While completing the bar, and giving birth to twins, she began actively campaigning for a Labour seat. She was unsuccessful, initially, but, in 1959, she won the seat. From there, she moved rather rapidly through the ranks, and in 1970, she was appointed Secretary of State for Education and Science. In 1979, she was elected as the United Kingdom's first female Prime Minister. She would hold the position for the next eleven years. Though she went undefeated for many years in elections, her approval rating was one of the lowest ever. However, she was recently ranked as the most competent British Prime Minister of the last 30 years according to an Ipsis MORI poll.