The six-times-a-week service will start on July 14 and it will go daily in winter 2016.
The Heathrow service will be operated by a four-class Boeing 777.
Neil Cottrell, British Airways’ head of network planning, said: “Iran is a large and growing economy and Tehran is a brilliant business city so we are incredibly excited to be adding another gateway to the Middle East for our customers.
“The recent lifting of sanctions opens up exciting new prospects for Iran as a tourist destination and with its rich heritage, unique architecture and world-class food it’s unsurprising Tehran is tipped to be a popular destination for 2016.”
