Senioritis is a term used colloquially to describe the decreased motivation towards studies displayed by students who are nearing the end of their high school or college careers. It is typically said to include slowness, procrastination, apathy regarding school work, and a tendency towards truancy. Many of these high school and college students find themselves in a sort of lame duck situation with a new chapter in life already waiting for them, and finishing the term is just a formality. "Senioritis" is a jocular term rather than a medical one, and is not recognized by the American Psychological Association as a distinct illness. It is considered similar to affective psychological disorders, such as depression or anxiety.

While senioritis is generally viewed as an imaginary disease, its effects are well known to many educators and students alike. This imagined affliction is a symptom of students' complacency as many students feel they are all but guaranteed their place in college, graduate school, or employment. At the high school level, college admission letters arrive in early spring, which affect high school seniors' motivation to push themselves academically for the rest of the school year; it is then said that "Senioritis has 'kicked in.'" Likewise, a college student may be faced with job opportunities or graduate school acceptance causing them to similarly lose interest or motivation in finalizing their remaining undergraduate studies.