The dollar fell to its lowest since late September against a basket of currencies on Friday as investors grew optimistic about the strength of the euro zone's recovery and lost appetite for the greenback.
The euro hit its highest since Sept. 25 against the dollar, up 0.65 percent on the day and more than 1 percent for the week. It was the single currency's third straight week of gains, its best run since July, and second straight 1 percent weekly gain.
Against the Japanese yen, the euro rose more than 1 percent to its highest since Nov. 16.
On Thanksgiving Thursday, while markets in the U.S. were closed, euro zone business growth surveys showed surprise growth, supporting the European Central Bank (ECB) move last month to announce a throttling back of its monetary stimulus.
The currency bloc's latest Purchasing Managers' Index (PMI) readings suggest the upturn still has momentum.
The dollar index fell to its lowest since Sept. 26 at 92.79, having suffered its worst single-day decline in more than five months on Wednesday after minutes from the Federal Reserve's latest meeting showed some policymakers were concerned about stubbornly weak U.S. inflation.
For the week, the dollar index fell nearly 1 percent, its worst weekly loss since September.
Analysts also pointed to developments in Germany, where the Social Democrats appear close to renewing their coalition co-operation with Chancellor Angela Merkel, as providing support to the euro.
"The euro zone economies are growing smartly," said Joseph Trevisani, chief market strategist at Worldwide Markets in Woodcliff Lake, New Jersey. "A further reduction or halt to the (ECB's) bond purchases is perfectly plausible if growth continues to improve."
Minutes from the ECB's latest policy meeting, released on Thursday, showed policymakers had broadly agreed on extending their quantitative easing scheme, albeit at a lower level, but keeping asset purchases open-ended appeared to generate fiercer debate.
The euro makes up more than 50 percent of the dollar index's weight.
Sterling rose to its highest against the dollar since Oct. 2 as markets interpreted the latest comments from top European Union policymakers as mildly positive for Brexit negotiations.
The pound pared gains after reports of a shooting on London's Oxford Street but remained higher on the day at $1.3326. Police later said they had found no evidence of gunfire or casualties in Oxford Street.