This Element focuses on extensive reading (ER), a language learning and teaching approach that encourages language learners to read a large amount of interesting and level-appropriate reading materials. Extensive reading has been adopted across educational spectrums, including higher, secondary, and elementary levels, and implemented in diverse language contexts such as English, Chinese, Italian, Spanish, and French. The primary objective of this Element is to offer comprehensive insights into the theoretical foundations of ER, analyze its multifaceted benefits to language learning, address the challenges encountered in its implementation, and propose effective strategies drawn from research for these challenges. The Element concludes with an overview of the latest trends and developments in ER.