Oleogelation the process of structuring liquid oils into solid-like gels using minimal amounts of gelators has emerged as a promising strategy to replace traditional solid fats in foods with healthier alternatives. A wide range of oleogelators has been studied, from low-molecular-weight compounds (waxes, monoglycerides, fatty alcohols) to polymeric materials (e.g., ethylcellulose); this review highlights the recent innovation of utilizing dietary fibers as oleogelators in structured lipid systems. Dietary fibers such as cellulose, pectin, and inulin can interact with oils via particle network formation or polymer entanglement, creating three-dimensional gel matrices that immobilize the oil and yield semi-solid oleogels with butter-like texture. The mechanism of fiber-based oleogelation is discussed in depth, revealing how factors like fiber particle size, molecular structure, and processing conditions influence gel formation and stability. Fiber-structured oleogels effectively mimic the functional properties of saturated fats in various food applications (e.g., spreads, bakery products, and processed meats) while offering significant health advantages. Replacing conventional solid fats (rich in saturated and trans fats) with fiber-based oleogels formulated from unsaturated oils leads to a markedly improved nutritional profile, characterized by a healthier fatty acid composition and added dietary fiber. These oleogels can thereby help reduce saturated fat intake and increase fiber consumption, contributing to better cardiovascular health and metabolic outcomes. Additionally, fiber oleogels may enhance oxidative stability of oils and serve as carriers for bioactive lipophilic nutrients, further broadening their functional benefits. The review surveys current food applications, demonstrating that fiber oleogels can maintain desirable texture, mouthfeel, and stability in products ranging from margarine alternatives and shortening replacers to fat-reduced meat and dairy analogues. Furthermore, the use of natural fibers as structuring agents aligns with clean-label and sustainability trends by avoiding artificial additives and reducing reliance on palm oil and hydrogenated fats and enabling the upcycling of agricultural fiber byproducts. Despite the promise of fiber-based oleogels, challenges remain in optimizing their gelling efficiency, sensory attributes, and long-term stability. Future research directions include modification of fibers or co-oleogelator strategies to fine-tune gel properties, as well as comprehensive evaluations of their performance in complex food matrices, consumer acceptance, and regulatory status. Overall, this review underscores the novelty and significance of fiber-based oleogels as a transformative approach to create healthier, fiber-enriched, and sustainable fat replacers, capable of improving the nutritional profile of foods without compromising quality or sensory appeal. Altogether, fiber-based oleogel technology holds great promise for next-generation food formulations aimed at health and sustainability.