Dysmenorrhea is one of the reproductive health disorders often experienced by adolescent girls, which can affect learning activities and quality of life. Lack of knowledge about dysmenorrhea can lead to improper management and prevention efforts. Health education is one of the interventions that can improve adolescent girls’ understanding of dysmenorrhea.
Method: This study used a quasi-experimental design with a one group pretest-posttest approach. The population consisted of all female students at SMA Islam Sultan Agung 3 Semarang, with a total sample of 82 respondents selected using purposive sampling technique. The research instrument was a knowledge questionnaire about dysmenorrhea. Data were analyzed using the Wilcoxon Signed Rank Test.
Result: The results showed an increase in the knowledge level of adolescent girls after being given health education about dysmenorrhea, with a p-value = 0.001 (p<0.05).
Conclusion: There is an effect of health education about dysmenorrhea on increasing the knowledge of adolescent girls at SMA Islam Sultan Agung 3 Semarang.

Keywords: health education, dysmenorrhea, knowledge