The euro rose above $1.12 for the first time in more than a month, while the yen hit its strongest in three weeks.
Gold rose as the dollar hit a low against the euro, after last week's soft U.S. growth data dented expectations for rate hike.
Stocks closed mixed in choppy trade, amid falling oil prices while investors digested economic data.
European stocks ended mostly in the red on Monday as investors reacted to banking stress tests and new manufacturing data.
Asia markets were mostly higher on Monday, with Chinese mainland shares falling, as traders digested weak Chinese PMI data.
The dollar recovered after its poorest weekly performance in three months, while the yen weakened after surging more than 3 percent.
U.S. crude prices on Monday settled sharply lower after briefly breaking below $40 a barrel for the first time since April.
Gold steadied on Monday, retreating from a near three-week high hit in the previous session.
U.S. stocks closed mixed Friday, the last trading day of the month, as encouraging earnings from major tech companies offset negative reports from some energy firms and a disappointing GDP report.
U.S. government debt yields were lower on Friday morning as U.S. gross domestic product for the second quarter missed economists' expectations.
European stocks recovered to close in the black on Friday as investors worked their way through another raft of European earnings.
Japan shares whipsawed and the yen surged after the BOJ threw markets a smaller-than-expected bone in its keenly watched decision on Friday.
Oil prices steadied on Friday amid short-covering after a week-long selloff but were on track to end the month about 15 percent lower.
Gold hit a near three-week high on Friday after much slower-than-expected U.S. economic growth weighed on the dollar.
The yen soared against the dollar after a round of modest monetary policy easing from the Bank of Japan disappointed investors.
U.S. stocks closed mostly higher Thursday, amid declines in oil prices, as major tech stocks gained.
U.S. government debt prices edged lower Thursday afternoon following the auction of $28 billion in seven-year notes.
European stocks finished in the red on Thursday as investors waded through another raft of earnings and prepared for the latest BOJ decision.
U.S. stock index futures pointed to a mostly lower open Friday amid earnings and after second-quarter GDP showed a 1.2 percent annualized growth rate.
Asia markets closed mixed on Thursday as investors digested fresh earnings reports and awaited the outcome of the Bank of Japan's two-day policy meeting.