Background Currently, only a few specific blood pressure-lowering medications are recommended for migraine prevention. Whether benefits extend to other classes or drugs is uncertain. Methods Embase, MEDLINE, and the Cochrane Central Registry of Controlled Trials were searched for randomized control trials on the effect of blood pressure-lowering medications compared with placebo in participants with episodic migraine. Data were collected on four outcomes – monthly headache or migraine days, and monthly headache or migraine attacks, with a standardised mean difference calculated for overall. Random effect meta-analysis was performed. Results In total, 50 trials (70% of which were crossover) were included, comprising 60 comparisons. Overall mean age was 39 years, and 79% were female. Monthly headache days were fewer in all classes compared to placebo, and this was statistically significant for all but one class: alpha-blockers −0.7 (95% CI: −1.2, −0.1), angiotensin-converting enzyme inhibitors −1.3 (95% CI: −2.9, 0.2), angiotensin II receptor blockers −0.9 (−1.6, −0.1), beta-blocker −0.4 (−0.8, −0.0) and calcium channel blockers −1.8 (−3.4, −0.2). Standardised mean difference was significantly reduced for all drug classes and was separately significant for numerous specific drugs: clonidine, candesartan, atenolol, bisoprolol, metoprolol, propranolol, timolol, nicardipine and verapamil. Conclusion Among people with episodic migraine, a broader number of blood pressure-lowering medication classes and drugs reduce headache frequency than those currently included in treatment guidelines. Trial Registration: The study was registered at PROSPERO (CRD42017079176).