Operating profit for the three months ended September fell to 562.7 billion yen ($3.79 billion), well short of an average estimate of 772.2 billion yen in a poll of 12 analysts by Refinitiv.
A year earlier, Toyota sales reported a 749.9 billion yen profit.
Toyota said it now expects to produce 9.2 million vehicles this fiscal year, down from the previously forecast 9.7 million but still ahead of last financial year's production of 8.6 million units.
Amid the gloom, shares in Toyota fell more than 2%, versus a 0.1% rise in the Nikkei (.N225) average.
Toyota estimated in August that materials costs for the full year will be 1.7 trillion yen, a 17% increase from previous estimate.