The deal also includes electronic warfare gear and support equipment, the contractor said in a statement.
The contract builds on an initial $233 million award Lockheed Martin received in June 2008 to commence the production of the aircraft.
The Rafale jet produced by France's Dassault was among other bids competing for the Moroccan deal.
Dassault has yet to sell any of its Rafale abroad, but French Defense Minister Herve Morin said recently he remains "resolutely optimistic" about the export prospects of the Rafale.
"We are having advance discussions with the United Arab Emirates, Brazil and also other partners," Morin told French media recently.
The F-16, however, is one of the world's most popular combat aircraft. More than 4,300 have been manufactured for orders put in by a total of 24 countries, including Belgium, Chile, Egypt, Israel, Poland, Thailand, Greece and Turkey.
"This contract represents a big strategic win for Lockheed Martin -- export sales to North Africa have often been mentioned and this is a move that will ensure the company gains a foothold in a growing market," aerospace analyst Say Ahmad was quoted telling the BBC.
In recent years the U.S. defense corporation has seen the cancellation of a number of prominent programs such as the TSAT Mission Operations System contract and the F-22 Raptor program.
"The addition of $841.9 million will boost the beleaguered backlog of the company, which had shrunk to $76.4 billion after the first nine months of fiscal 2009 from $80.9 billion at year-end fiscal 2008," reported the Zacks investment research Web site.
Lockheed Martin's high-cost platform programs have been top targets for the Obama administration's budget cuts.
Morocco is the 25th nation to buy the F-16.
In September Lockheed Martin signed a $30 million foreign military sales contract with the country's Royal Air Force to provide F-16 sniper target pods used with precision-guided weapons.
It is not clear whether the latest deal includes the Pratt and Whitney F100-229 engines or air-launched weapons.
In the same week Lockheed also won contracts to supply the Pentagon with "advanced countermeasure systems along with associated mission equipment and support elements," the Pentagon said in a statement.
Lockheed Martin remains a key player within the aerospace industry. It competes mainly with Boeing Co., Northrop Grumman Corp. and Embraer.