STOCKHOLM—China overtook the U.S. as the world's largest smartphone market by volume in the third quarter, according to a report by research firm Strategy Analytics.

Deliveries of smart phones to operators and retailers in China grew 58% in the third quarter from the previous quarter to 24 million units. That surpassed 23 million units delivered to the U.S. market, down 7% from the previous quarter, according to the report.

The...