This review focuses on the recent developments in the preparation, crystal structure, luminescence, and applications of silicon-based oxynitride and nitride phosphors for white light-emitting diodes (LEDs). Silicon-based oxynitrides and nitrides, such as nitridosilicates, nitridoluminosilicates, oxonitridosilicates, oxonitridoluminosilicates, and sialons, are built from networks of crosslinked SiN₄ tetrahedra, which significantly lower the excited state of rare-earth elements' 5d electrons due to large crystal-field splitting and a strong nephelauxetic effect. This enables these phosphors to absorb blue-to-green light efficiently and emit across the visible spectrum, making them suitable for use in white LEDs. The structural versatility of these phosphors allows for the emission of all colors (blue, green, yellow, and red), and they have demonstrated superior performance in white LEDs, including high luminous efficacy, high chromatic stability, a wide range of white light with adjustable correlated color temperatures (CCTs), and brilliant color-rendering properties. The review also discusses the synthesis methods, including solid-state reaction, gas-reduction nitridation, and carbothermal reduction and nitridation, and highlights the applications of these phosphors in bichromatic and multichromatic white LEDs.This review focuses on the recent developments in the preparation, crystal structure, luminescence, and applications of silicon-based oxynitride and nitride phosphors for white light-emitting diodes (LEDs). Silicon-based oxynitrides and nitrides, such as nitridosilicates, nitridoluminosilicates, oxonitridosilicates, oxonitridoluminosilicates, and sialons, are built from networks of crosslinked SiN₄ tetrahedra, which significantly lower the excited state of rare-earth elements' 5d electrons due to large crystal-field splitting and a strong nephelauxetic effect. This enables these phosphors to absorb blue-to-green light efficiently and emit across the visible spectrum, making them suitable for use in white LEDs. The structural versatility of these phosphors allows for the emission of all colors (blue, green, yellow, and red), and they have demonstrated superior performance in white LEDs, including high luminous efficacy, high chromatic stability, a wide range of white light with adjustable correlated color temperatures (CCTs), and brilliant color-rendering properties. The review also discusses the synthesis methods, including solid-state reaction, gas-reduction nitridation, and carbothermal reduction and nitridation, and highlights the applications of these phosphors in bichromatic and multichromatic white LEDs.