"It is possible to give those 12 howitzer tanks to Lithuania," German Defence Minister Ursula von der Leyen told journalists in Vilnius.
Von Der Leyen did not disclose the price, but said experts would invoke a "solidarity" clause when they finalise the deal next month.
German media reported the hardware was used by Berlin in Afghanistan and is now worth €15 million.
"We are interested in moving fast," Lithuanian army colonel Romualdas Petkevicius in charge of weapon procurement told AFP, adding he hoped the hardware would arrive next year.
Lithuania is seeking "PzH 2000"-type howitzers. Petkevicius said the Baltic state was also mulling whether to buy German Boxer-type armoured fighting vehicles.
Under Moscow's thumb until 1991, Lithuania along with fellow Baltic states Estonia and Latvia launched a concerted drive to boost defences since Russia annexed Crimea from Ukraine last year.
NATO members since 2004, the three Baltic states have repeatedly asked allies to step up their presence to deter Russia.
Berlin will send over 500 troops to Lithuania for military exercises this year.
NATO is also reinforcing its defences on Europe's eastern flank with a rapid reaction force of 5,000 troops and command centres in six formerly communist members of the alliance, including the three Baltic states.