Saigon Jewelry Company gold bar dropped 0.77% to VND142 million (US$5,488.88) per tael. A tael equals 37.5 grams or 1.2 ounces.
Gold ring declined 0.56% to VND142 million per tael. Gold prices in Vietnam have fallen 7.07% so far this year.
Globally gold prices edged lower on Monday, pressured by a firm dollar and elevated US Treasury yields, while investors awaited the Federal Reserve's policy decision next week, when officials are expected to leave interest rates unchanged, Reuters reported.
Spot gold fell 0.4% to $4,147.87 per ounce. U.S. gold futures for December delivery settled 0.5% lower at $4,160.10 per ounce.
The U.S. dollar edged up, making greenback-denominated gold more expensive for holders of other currencies, and 10-year U.S. Treasury yields rose 0.6%.
"There are concerns that central banks will have to tighten their policies further to control inflation, which is providing yields another boost," said Fawad Razaqzada, market analyst at Forex.com.
"And with yields remaining elevated, gold investors are wondering whether it makes more sense to be in the bond market right now."