Cross-country skiing (or XC skiing) is a form of ski touring in which participants propel themselves across snow-covered terrain using skis and poles. The activity is popular in many places with large snowfields, primarily Northern Europe, Canada, and Alaska.

Cross-country skiing is part of the Nordic skiing sport family, which includes ski jumping, Nordic combined (cross-country skiing and ski jumping), Biathlon (skiing and rifle marksmanship) and ski-orienteering (which includes map navigation along snow trails and tracks). Cross-country skiing is the modern style of skiing that most resembles prehistoric skiing, particularly when done in the backcountry. It is also related to Telemark skiing.