BEIJING—China’s economic slowdown is widely expected to continue into next year, increasing pressure on Beijing leaders to take more-strenuous growth-spurring measures and to continue moving slowly on their plans for fundamental economic reform.

On Tuesday, China reported that gross domestic product expanded at 7.3% in the third quarter from a year earlier, the slowest rate of growth in more than five years, as deepening problems in the housing market, sluggish retail sales and expanding debt weighed on the economy. Many analysts...