The parliament, in which the rightwing government has a majority, endorsed plans by Defence Minister Antoni Macierewicz to raise the budget from the current 2 percent of GDP to 2.5 percent by 2030.
Under this plan, spending is initially expected to reach 2.1 percent by 2020.
US President Donald Trump has laid on the pressure for European NATO allies to hike their defence budgets, saying they do not pay enough for their security.
So far only five NATO members have met the benchmark set in 2014: the US, Greece, Britain, Estonia and Poland.
Romania is set to join them this year, and Latvia and Lithuania in 2018, according to NATO chief Jens Stoltenberg.
Troop numbers in Poland are also expected to grow from 130,000 to 200,000, by 2030, including 130,000 professional soldiers. The rest will be reserves.
Poland's spending hike comes as tensions between Russia and NATO peak over the Kremlin's meddling in Ukraine and the US-led alliance bolstering its forces in eastern Europe.
NATO has stationed four international battalions in eastern Europe as tripwires against possible Russian adventurism in the region.
Separately, the US Army also set up a new European headquarters in Poland in May to command some 6,000 of its troops deployed in NATO and Pentagon operations across the alliance's eastern flank since the beginning of the year.
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![Ukrainian President, Volodymyr Zelensky and US President Joe Biden [BBC]](data:image/svg+xml;charset=utf8,%3Csvg%20xmlns%3D'http%3A%2F%2Fwww.w3.org%2F2000%2Fsvg'%20width%3D'300'%20height%3D'172'%20data-ring-placeholder%3D'1'%3E%3C%2Fsvg%3E "Ukrainian President, Volodymyr Zelensky and US President Joe Biden [BBC]")
