The Institute for Supply Management said its services index fell to 53.9 last month from 55.4 in October. The reading was below a forecast for 55.0, according to a Reuters survey of economists.
A reading above 50 indicates expansion in the sector. November marked the 47th-straight month of growth in the services sector.
The employment gauge fell to 52.5 from October's 56.2 to hit its lowest since May, while business activity growth slowed to 55.5 last month from 59.7 in October.