Cellulose paper, as one of the four great inventions of China, possesses admirable properties like biocompatibility, biodegradability, and low cost and is a promising alternative to conventional substrates for perovskite solar cells (PSCs). In article no. 1800175, Bingqiang Cao, Jinghua Yu, and co‐workers fabricate a flexible holetransport‐ material‐free PSC with a power conversion efficiency of 9.05% on the cellulose paper, for the first time, which could be utilized in wearable electronics.