Primary Dysmenorrhea (PD) is period (menstrual) pain without any underlying structural or pathological changes in the pelvis causing it. In contrast, secondary dysmenorrhea is associated with some kind of pathology causing the pain and commonly includes endometriosis, adenomyosis, and fibroids. PD affects 45–95% of females during their reproductive lifespan. PD is characterized by cramping pain in the lower abdomen before or during the menstrual period, with the pain typically beginning within hours of onset of menstruation and peaking during the first few days of the cycle. Accompanying symptoms can include nausea, vomiting, diarrhea, fatigue, headache, light headedness, anxiety, and poor sleep. PD is also associated with increased pain sensitivity in other parts of the body. The underlying pathomechanisms of PD are complex and are understood to involve excessive contractility of the myometrium, reduced uterine blood flow and excessive release of inflammatory mediators called prostaglandins, as well as other inflammatory markers, and central changes to pain pathways. Current treatments for PD are focused on pain relief but just under 50% report inadequate symptom control with analgesics, as well as often being associated with side effects. The endocannabinoid system (ECS) is responsible for regulation of pain and analgesia, found within components of the pain pathways and extensively in the female reproductive organs, and involved in myometrial contractility. Components of cannabis interact directly and indirectly with the ECS, which may be an important therapeutic target for treatment of PD. The analgesic and anti-inflammatory actions of tetrahydrocannabinol (THC) and cannabidiol (CBD) are already well established and both also have anti-nausea actions. Preclinical research shows that anandamide, THC, synthetic agonists of cannabinoid receptors, a synthetic isomer of CBD, and synthetic agonists of TRPV4 ion channels reduce human myometrial contractility. Medicinal cannabis (MC) has been shown to be effective in reducing chronic pain, in particular neuropathic pain in many studies including systematic reviews and randomized controlled trials, but there have been very few clinical studies in relation to PD. Surveys in women with chronic pelvic pain broadly suggest that MC is effective in reducing pain, and a survey and observational studies in female cannabis users indicate increased cannabis use in the premenstrual phase and during menses. An open-label study of CBD isolate in women with PD found evidence of benefit over 3 months. Qualitative research indicates dissatisfaction with current PD strategies is a key driver for women wanting to use MC for this condition. Clinical research is desperately needed.