Pyromania is an impulse-control disorder in which individuals repeatedly fail to resist impulses to deliberately start fires, to relieve some tension or for instant gratification. The term pyromania comes from the Greek word πῦρ (pyr, 'fire'). Pyromania is distinct from arson, which is the deliberate setting of fires for personal, monetary or political gain. Pyromaniacs start fires to release anxiety and tension, or for arousal. Other impulse-control disorders include kleptomania and intermittent explosive disorder.

There are specific symptoms that separate pyromaniacs from those who start fires for criminal purposes or due to emotional motivations not specifically related to fire. Someone with this disorder deliberately and purposely sets fires on more than one occasion, and before the act of lighting the fire the person usually experiences tension and an emotional buildup. When around fires, a person with pyromania gains intense interest or fascination and may also experience pleasure, gratification or relief. Another long term contributor often linked with pyromania is the buildup of stress. When studying the lifestyle of someone with pyromania, a buildup of stress and emotion is often evident; this is seen in teenagers' attitudes towards friends and family. At times it is difficult to distinguish the difference between pyromania and experimentation in childhood because both involve receiving gratitude from fire.

The World Health Organization's International Classification of Diseases (11th Revision) ICD-11, regarded as the global standard, was released in June 2018 and came into full effect from January 2022. It states the following about pyromania:

Pyromania is characterised by a recurrent failure to control strong impulses to set fires, resulting in multiple acts of, or attempts at, setting fire to property or other objects, in the absence of an apparent motive (e.g., monetary gain, revenge, sabotage, political statement, attracting attention or recognition). There is an increasing sense of tension or affective arousal prior to instances of fire setting, persistent fascination or preoccupation with fire and related stimuli (e.g., watching fires, building fires, fascination with firefighting equipment), and a sense of pleasure, excitement, relief or gratification during, and immediately after the act of setting the fire, witnessing its effects, or participating in its aftermath.

— ICD-11, chapter 6, section C70

It also notes that pyromania has no relation to intellectual impairment, substance abuse, or other mental and behavioral disorder. ICD-11 was produced by professionals from 55 countries out of the 90 countries involved and is one of the most widely used reference worldwide by clinicians, with the other being the Diagnostic and Statistical Manual of Mental Disorders (DSM-5-TR from 2022, DSM-5 from 2013, or their predecessors).

The American Psychiatric Association's Diagnostic and Statistical Manual of Mental Disorders, First Edition (DSM-5), released in 1952, categorized pyromania as a subset of obsessive–compulsive disorder. In the Second Edition, the disorder was dropped. In the Third Edition, it returned under the category of impulse-control disorders.

The Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, Text Revision (DSM-5-TR), released in 2022, states that the essential feature of pyromania is "the presence of multiple episodes of deliberate and purposeful fire setting." Pyromania moved from the DSM-IV chapter "Impulse-Control Disorders Not Otherwise Specified," to the chapter "Disruptive, impulse-control, and conduct disorders" in the DSM-5.