In this paper, we investigated the impacts of varying CeO2 contents and heat‐treatment procedures on the crystallization, and microstructure, and dielectric characteristics of MgO‐Al2O3‐SiO2‐TiO2‐CeO2 (MASTC) materials. The research indicated that perrierite, and rutile, and α‐cordierite were the major crystalline phases in the materials. An increased CeO2 content promoted the formation of perrierite and inhibited the precipitation of α‐cordierite and rutile in the glass‐ceramics. An appropriate amount of CeO2 content contributed to a dense microstructure and improved the dielectric characteristics of the samples. However, an excessive amount of CeO2 deteriorated the densification and dielectric characteristics of the MASTC materials. Furthermore, heat‐treatment temperature and duration also had a significant impacts on the crystallization, microstructure, and dielectric performance of the materials. The MASTC material with 20.2 wt% CeO2, heat‐treated at 1100 oC for a duration of 3 h possessed superior characteristics with a density of 3.14 g/cm3, a permittivity of 11.1, and a Q×f factor of 17357 (14 GHz).This article is protected by copyright. All rights reserved.