Interrupting their holidays for the second time this summer to cast ballots on a Greek rescue, lawmakers in the Bundestag lower house appoved the 86-billion-euro (USD 95-billion) rescue by 454 votes to 113.
Eighteen abstained and attendance was markedly lower than during a vote last month approving the start of negotiations on the package.
While the approval was virtually guaranteed given the dominance of Merkel's left-right "grand coalition,"the key question was whether the chancellor would face damaging dissent within her own camp.
Germany's powerful finance minister, Wolfgang Schaeuble, had opened the debate telling MPs it would be "irresponsible" not to approve a third bailout for Greece.
He said Athens had earned a fresh opportunity to salvage its economy with the help of its eurozone partners, including its de-facto paymaster Germany.
"There is no guarantee that all of this will work and there can always be doubts," he said.
Underlining the controversy throughout the eurozone surrounding the latest lifeline for Athens, Dutch Prime Minister Mark Rutte was to face a grilling in his own parliament, and a possible no-confidence vote, over his cabinet's support for the bailout.
The Bundestag's blessing was required for German participation in the latest Greek bailout plan.
But grumbling has grown ever louder within Merkel's Christian Union bloc over help extended to the Greek government of leftist Prime Minister Alexis Tsipras.
