This review outlines the fundamentals and current status of tandem photovoltaics (PV), considering various PV technology pairings and architectures. Tandem PV, which combines two or more junctions, offers the potential for significantly higher efficiencies (up to >40%) and lower embodied carbon, making it a promising solution for sustainable energy. However, much work remains to translate lab-scale successes into commercial products. The article discusses the challenges that must be overcome, including improving cell efficiencies, ensuring reliability and durability, and reducing costs. It also presents a roadmap for future development, emphasizing the need for collaboration between researchers and manufacturers to address key aspects of tandem design, reliability, and scaling. The review highlights the importance of material selection, junction design, and the integration of different PV technologies to achieve optimal performance. It also discusses the potential of hybrid tandems with two junctions fabricated from established and emerging PV technologies, rather than high-efficiency, high-cost III–V multijunction cells. The article provides an overview of different terminal configurations for tandem devices, including 2T, 3T, and 4T architectures, and discusses the challenges associated with each. It also covers the fundamental efficiency limits of tandem PV, the energy-harvesting efficiency, and the value proposition of tandem PV in terms of cost, performance, and environmental impact. The review concludes with a roadmap for future development, emphasizing the need for continued research and collaboration to enable the commercialization of tandem PV technologies.This review outlines the fundamentals and current status of tandem photovoltaics (PV), considering various PV technology pairings and architectures. Tandem PV, which combines two or more junctions, offers the potential for significantly higher efficiencies (up to >40%) and lower embodied carbon, making it a promising solution for sustainable energy. However, much work remains to translate lab-scale successes into commercial products. The article discusses the challenges that must be overcome, including improving cell efficiencies, ensuring reliability and durability, and reducing costs. It also presents a roadmap for future development, emphasizing the need for collaboration between researchers and manufacturers to address key aspects of tandem design, reliability, and scaling. The review highlights the importance of material selection, junction design, and the integration of different PV technologies to achieve optimal performance. It also discusses the potential of hybrid tandems with two junctions fabricated from established and emerging PV technologies, rather than high-efficiency, high-cost III–V multijunction cells. The article provides an overview of different terminal configurations for tandem devices, including 2T, 3T, and 4T architectures, and discusses the challenges associated with each. It also covers the fundamental efficiency limits of tandem PV, the energy-harvesting efficiency, and the value proposition of tandem PV in terms of cost, performance, and environmental impact. The review concludes with a roadmap for future development, emphasizing the need for continued research and collaboration to enable the commercialization of tandem PV technologies.