Sexting is sending, receiving, or forwarding sexually explicit messages, photographs, or videos, primarily between mobile phones. It may also include the use of a computer or any digital device. The term was first popularized early in the 21st century and is a portmanteau of sex and texting, where the latter is meant in the wide sense of sending a text possibly with images. Sexting is not an isolated phenomenon but one of many different types of sexual interaction in digital contexts that is related to sexual arousal.

The first published use of the term sexting was in a 2005 article in the Australian Sunday Telegraph Magazine. In August 2012, the word sexting was listed for the first time in Merriam-Webster's Collegiate Dictionary.

The Pew Research Center commissioned a study on sexting, which divides the practice into three types:

Sexting has become more common with the rise in camera phones and smartphones with Internet access, that can be used to send explicit photographs as well as messages. While sexting is done by people of all ages, most media coverage fixates on negative aspects of adolescent usage. Young adults use the medium of the text message much more than any other new media to transmit messages of a sexual nature, and teenagers who have unlimited text messaging plans are more likely to receive sexually explicit texts.

As a result of sexting being a relatively recent practice, ethics are still being established by both those who engage in it and those who create legislation based on this concept. Whether sexting is seen as a positive or negative experience typically rests on the basis of whether or not consent was given to share the images. Nevertheless, Australian laws currently view under-18s as being unable to give consent to sexting, even if they meet the legal age for sexual consent.

Contrary to common misconception, when it comes to preventing abuse among adolescents, consent is more important than trying to stop sexting altogether.

Sexting has been promoted further by several direct messaging applications that are available on smartphones. The difference between using these applications and traditional texting is that content is transmitted over the Internet or a data plan, allowing anyone with Internet access to participate.

Snapchat appeals to teens because it allows users to send photos for a maximum of ten seconds before they disappear. Many sending photos over Snapchat believe these photos will disappear without consequences, so they feel more secure about sending them. There have been several cases where teens have sent photos over these applications, expecting them to disappear or be seen by the recipient only, yet are saved and distributed, carrying social and legal implications.