A sophomore slump (also known as a sophomore jinx or sophomore jitters) is when a sophomore fails to live up to the relatively high standards that occurred during freshman year.

It is commonly used to refer to the apathy of students (second year of high school, college or university), the performance of athletes (second season of play), singers/bands (second album), television shows (second seasons), films and video games (sequels/prequels).

In the United Kingdom, the "sophomore slump" is more commonly referred to as "second year blues", particularly when describing university students. In Australia, it is known as "second year syndrome", and is particularly common when referring to professional athletes who have a mediocre second season following a stellar debut.

The phenomenon of a "sophomore slump" can be explained psychologically, where earlier success has a reducing effect on the subsequent effort, but it can also be explained statistically, as an effect of the regression towards the mean.