Kārtika (Bengali: কার্তিক Kartik, Hindi: कार्तिक Kārtika, Odia: କାର୍ତ୍ତିକ Kārttika, Gujarati: કારતક Kārtak, Kannada: ಕಾರ್ತಿಕ , Maithili: कातिक, Marathi: कार्तिक, Nepali: कार्त्तिक, Sanskrit: कार्तिक, Telugu: కార్తీకం, Tamil: கார்த்திகை) is the eighth month of the Hindu calendar, which falls in October and November of the Gregorian calendar. In India's national civil calendar, Kartika is the eighth month of the year, beginning on 23 October and ending on 21 November.

In most Hindu calendars, Kartika begins with the transit of the Sun into Libra, beginning on 18 October and lasting until 15 November. In the Nepali calendar, which is also the country's official calendar, Kartika is the seventh month of the year, similar to the Maithili and Bengali calendars. In Bengal, Kartika marks the start of the dry season (হেমন্ত Hemôntô). In the solar Tamil calendar, Kārttikai (கார்த்திகை, /kɑːrt̪iɡəj/) is the eighth month, corresponding to November/December in the Gregorian calendar. It begins when the sun enters the sign of Scorpio. Many festivals, such as Karthikai Deepam, are celebrated in this month.