The company had sold 3,29,833 units in July 2016.
Its motorcycle sales also dropped 7 per cent to 2,65,182 units as against 2,85,527 units in July last year, Bajaj Auto said in a BSE filing.
The two-wheeler major said its exports fell 8 per cent during the month to 1,21,230 units, from 1,31,811 units in the year-ago period.
In the commercial vehicle category, Bajaj Auto's sales in July went down 4 per cent to 42,545 units compared to 44,306 units earlier.