Multishell Y2O3:Yb3+/Er3+ hollow spheres with uniform morphologies and controllable inner structures are prepared successfully by using a glucose‐template hydrothermal process followed by temperature‐programmed calcination. Much enhanced upconverted photoluminescence of these Y2O3:Yb3+/Er3+ are observed, which are due to the multiple reflections and the enhanced light‐harvesting efficiency of the NIR light resulting from the special features of the multishell structures.