Fermentable oligo-, di-, monosaccharides and polyols (FODMAPs) are carbohydrates which can cause symptoms of irritable bowel syndrome (IBS). Cereal-based products are high in FODMAPs, as they are part of the carbohydrate fraction in flour. Low-FODMAP products are starch-based which leads to a low dietary fibre content. Hence, the fortification with dietary fibre ingredients low in FODMAPs is essential. This study reveals the impact of three different fibre ingredients, resistant starch, cellulose, and arabinoxylan, and their interactions with each other in a low-FODMAP biscuit model system using response surface methodology. All fibre ingredients have an affinity to water which was further increased by their coexistence in the model system. Fibersym RW affected the biscuit hardness by its morphology and potential to recrystallise leading to a maximum inclusion level of 40%. VITACEL L 600-30 also increased biscuit hardness due to its plasticising character leading to a maximum inclusion of 20%. AgriFiber BFG mainly impacted the colour of the product restricting its inclusion to 2.3%. Additionally, it reduced the degree of starch digestibility of the biscuit by the formation of a film imbedding the starch granules and reducing enzyme attack. This research provides an in-depth insight into the integration potential of these fibre ingredients into a low-FODMAP biscuit, their interactions within the system and inclusion levels which allow their coexistence.