It seems logical that smoking may increase your risk of snoring. The irritating smoke may cause inflammation and disruption of your upper airway, especially your nasal passage and throat. It may cause increased airway congestion. This disruption may lead to vibration as air moves through, leading to the unpleasant sound of snoring.
Large research studies actually support these proposed associations. In one study of 811 adults, the risk of snoring was 2.3 times greater among current smokers. In another large study of 15,555 people, snoring occurred more commonly among current smokers (24 percent) compared to former smokers (20 percent) and never smokers (14 percent).
The risk of snoring seems to correlate with the amount of smoking. In other words, if you smoke more heavily, the risk of snoring is likewise increased. It is uncertain if this increased airway resistance can lead to a collapse of the airway called sleep apnea. Moreover, the role of nicotine withdrawal or nasal congestion in this phenomenon is not fully understood.
Nevertheless, if you smoke, snoring may be another reason for you to finally quit.
Wetter et al. "Smoking as a risk factor for sleep-disordered breathing." Arch Intern Med 1994;154:2219.
Franklin, KA et al. "The influence of active and passive smoking on habitual snoring." Am J Respir Crit Care Med 2004;170:799.