Background Medication-overuse headache is prevalent, but in principle preventable. Objective To describe the Danish national awareness campaign for medication-overuse headache. Methods The Danish Headache Center, the Association of Danish Pharmacies, and headache patient organizations implemented a four-month medication-overuse headache awareness campaign in 2016. Target groups were the general public, general practitioners, and pharmacists. Key messages were: Overuse of pain-medication can worsen headaches; pain-medication should be used rationally; and medication-overuse headache is treatable. A range of communication technologies was used. A survey on the public's awareness of medication-overuse headache was conducted. Results The Danish adult population is 4.2 million. Online videos were viewed 297,000 times in three weeks. All 400 pharmacies received campaign materials. Over 28,000 leaflets were distributed. Two radio interviews were conducted. A television broadcast about headache reached an audience of 520,000. Forty articles were published in print media. Information was accessible at 32 reputable websites and five online news agencies. Three scientific papers were published. Information was available at an annual conference of general practitioners, including a headache lecture. The survey showed an increase in percentage of the public who knew about medication-overuse headache (from 31% to 38%). Conclusion A concerted campaign to prevent medication-overuse headache can be implemented through involvement of key stakeholders.