The announcement came within an hour of an expected delay in air tax cuts by the Scottish Government, in another sign that current levels are not deterring airlines from expansion.
BA said its current daily flights between the Highland capital and the UK's hub airport would be doubled to twice daily on Wednesdays, Saturdays and Sundays from next March.
The extra return flights will operate between late afternoon and mid evening.
The airline relaunched the route last year after an 18-year absence.
BA Inverness manager Phyllis Stuart said, “We’re delighted to be able to offer our customers more flights from the Highland capital, offering more seats on the route after a successful start to the route.
“We, and our partners at Inverness Airport and the business communities in Inverness and the Highland region, have worked tirelessly to encourage business and leisure travellers to use the new route for the benefit of the businesses and individuals in the region.
“The increased frequency on the route is the result of that partnership, and further demonstrates British Airways’ long-standing commitment to the Highlands and Islands.”
Inglis Lyon, managing director of Scottish Government-owned Highlands and Islands Airports Limited (HIAL) , which includes Inverness, said: "The new schedule provides additional two-way connectivity with destinatons such as Atlanta, San Diego, Phoenix, Berlin and Mexico City.
“We can also anticipate more than 10 per cent additional inbound passengers to the Highlands and Islands to experience all the north of Scotland has to offer.”
Stewart Nicol, chief executive of Inverness Chamber of Commerce said, “This is excellent news for Inverness and the Highlands and Islands as it strengthens one of the most important routes out of Inverness Airport.
“BA’s commitment to Inverness and this route is most welcome and demonstrates the importance of the highland business community to their global network.”