CHENGDU, China—Beijing has managed to let the yuan slide against the dollar without sparking strong protests from its trading partners this year. Now, though, a bigger depreciation against a broader group of currencies is increasingly getting attention.

At the two-day meeting of Group of 20 finance chiefs over the weekend, held in this southwestern Chinese city, officials from some of China’s major trading rivals expressed concern over the yuan’s declines this year. It has fallen nearly 6% against a basket of 13 currencies...