<p>Titanium is widely regarded as a strategically important metal due to its outstanding properties and broad applications in metallurgy, aerospace, and energy sectors. However, with the gradual depletion of primary titanium ores, concerns over long-term supply security are becoming increasingly prominent. At present, less than 20% of titanium-bearing secondary resources are effectively utilized, while the majority are either stockpiled or discarded, resulting in both significant resource loss and environmental challenges. A comprehensive review of six representative titanium-bearing secondary resources, which were either derived from titanium production processes or contain relatively high levels of titanium, was conducted. These resources included titanium-bearing blast furnace slag, titanium-extracted tailings, ferrotitanium slag, titanium gypsum, spent selective catalytic reduction catalysts, and red mud. The chemical and mineralogical characteristics, utilization pathways, and underlying reaction mechanisms were systematically summarized. Particular attention was given to recent advances in extraction technologies for titanium recovery from these materials. From a practical standpoint, classifying and recycling these resources according to their intrinsic physicochemical properties could enable more targeted and efficient recovery strategies. Meanwhile, the development of low-carbon or carbon–neutral extraction technologies, together with environmentally benign leaching processes, remains highly desirable. Additionally, the integration of intelligent management systems for monitoring energy consumption, environmental impact, and economic performance will play a crucial role in advancing the sustainable utilization of titanium-bearing resources.</p>