Kamen Rider Zi-O (仮面ライダージオウ, Kamen Raidā Jiō) is a Japanese tokusatsu drama in the Toei Company's Kamen Rider franchise. It is the twenty-ninth Kamen Rider series overall as well as the twentieth and final installment in the Heisei period. The show premiered on September 2, 2018, following the finale of Kamen Rider Build, joining Kaitou Sentai Lupinranger VS Keisatsu Sentai Patranger and later, the miniseries Super Sentai Strongest Battle, followed by Kishiryu Sentai Ryusoulger, in the Super Hero Time line-up.

The series has a time travel/multiverse motif while paying tribute to all of the previous Heisei-era Kamen Riders due to being a spiritual sequel to Kamen Rider Decade. The series and related films also feature returning actors reprising their roles from the previous Heisei series.