Background General practitioners (GPs) diagnose and manage a majority of headache patients seeking health care. With the aim to understand the potential for clinical improvement and educational needs, we performed a study to investigate Norwegian GPs knowledge about headache and its clinical management. Methods We invited GPs from a random sample of 130 Norwegian continuous medical education (CME) groups to respond to an anonymous questionnaire survey. Results 367 GPs responded to the survey (73% of invited CME groups, 7.6% of all GPs in Norway). Mean age was 46 (SD 11) years, with an average of 18 (SD 10) years of clinical experience. In general the national treatment recommendations were followed, while the International Classification of Headache Disorders and other international guidelines were rarely used. Overall, 80% ( n  = 292) of the GPs suggested adequate prophylactic medication for frequent episodic migraine, while 28% ( n  = 101) suggested adequate prophylactic medication for chronic tension-type headache (CTTH). Half (52%, n  = 191)) of the respondents were aware that different types of acute headache medication can lead to medication-overuse headache (MOH), and 59% ( n  = 217) knew that prophylactic headache medication does not lead to MOH. GPs often used MRI in the diagnostic work-up. GPs reported that lack of good treatment options was a main barrier to more optimized treatment of headache patients. Conclusion The knowledge of management of CTTH and MOH was moderate compared to migraine among Norwegian GPs.