Preeclampsia (PE) is a common pregnancy complication characterized by hypertension, proteinuria, and end-organ dysfunction. However, to date, no effective treatment has been established other than iatrogenic delivery, and the importance of prevention as an alternative approach to addressing PE has been emphasized. There is growing evidence on the effectiveness of pharmacological and non-pharmacological prophylaxis in preventing PE. In this review, we focused on dietary supplements as non-pharmacological prophylaxis for PE. Calcium is a well-documented supplement for the prevention of PE. Daily 500 mg calcium supplementation can roughly halve the risk of PE in settings where calcium intake is low, including in Japan. According to recent systematic reviews and network meta-analyses, current evidence on the efficacy of vitamin D supplementation is inconsistent. Although vitamin D is a candidate for the prevention of PE, future large-scale randomized control trials are necessary to draw definitive conclusions. We also reviewed other dietary supplements, including vitamins (vitamins A, B6, C, and E, folic acid, and multivitamins), minerals (magnesium, zinc, and iron), amino acids (l-arginine and l-carnitine), anti-oxidants (lycopene, resveratrol, and astaxanthin), and other agents (omega-3 fatty acids, coenzyme Q10, melatonin, and s-equol). In this study, we provide a comprehensive approach to help develop better preventive strategies and ultimately reduce the burden of PE.