"When we talked about the contract, money was not an issue at all," Shakhtar's billionaire owner Rinat Akhmetov, Ukraine's richest man, told the club's website.
"I was interested in only one thing - did this team reach their maximum or could they make a step forward?"
The contract extension ends speculation about Lucescu's future after media reports linked the 67-year-old Romanian with wealthy Russian Premier League club Anzhi Makhachkala.
Lucescu has led Shakhtar to six domestic titles and the 2009 UEFA Cup since joining the mining-town club in 2004.
Shakhtar, who failed to reach the Champions League quarter-finals for the second year in a row this month, are on course to claim their fourth consecutive league crown this season, leading second-placed Metalist Kharkiv by 15 points with nine games left.
Lucescu, who has also coached Bucharest clubs Dinamo and Rapid, Turkey's Galatasaray and Besiktas and Inter Milan among others as well as Romania's national team, broke several ribs in a car crash in the Romanian capital in January last year.
Get the best features, fun and footballing frolics straight to your inbox every week.
Thank you for signing up to Four Four Two. You will receive a verification email shortly.
There was a problem. Please refresh the page and try again.