The merger of photoredox catalysis with transition-metal catalysis, termed metallaphotoredox catalysis, has enabled the development of a broad range of novel organic reactions. Photoredox catalysis is the activation of an organic molecule by single-electron transfer with an excited-state catalyst, typically generating a radical intermediate. The selective delivery of chemical energy to the catalyst by visible light allows for the generation of these reactive species under mild conditions. The union of this platform with transition-metal catalysis enables cross-coupling reactions of several bench-stable and widely available classes of sp3-hybridized starting materials that have historically been challenging or impossible to activate with transition metals alone. The photoredox catalyst can also modulate the oxidation state of the transition-metal catalyst, leading to new reactivity profiles. This chapter covers the types of carbon–carbon bonds that may be formed using this technology.