Pet food companies use fibrous ingredients in cat foods to aid weight and hairball management. Miscanthus grass could be an alternative novel fibre source for cat foods. The objectives of this work were to determine the effects of Miscanthus grass as a fibre source on nutrient utilization, stool quality and hairball management in cats. Dry extruded cat foods (average chemical composition; digestibility trial: 94.54% dry matter—DM, 34.47% crude protein—CP, 11.67% crude fat, 7.06% ash and 13.04% total dietary fibre—TDF; and hairball trial: 94.88% DM, 34.60% CP, 11.30% crude fat, 7.02% ash and 9.77% TDF) were fed to 12 cats for a 9‐day (digestibility trial) or 16‐day (hairball trial) adaptation period followed by a 5‐day total faecal collection period. Digestibility trial was performed as a replicated Latin square design, and the hairball trial was performed as a switchback design. In general, the cats fed the beet pulp diet (BPD) had higher DM, organic matter, gross energy and TDF digestibility than cats fed Miscanthus grass (MGD) or cellulose (CED) diet (p < .05). However, CP digestibility was lower for cats fed BPD (82.1 vs. 84.7 and 85.1%, respectively, for BPD, MGD and CED). These differences could be due to the differences in dietary fibre content and(or) composition. Faecal scores were lower for cats fed BPD (2.84) compared with MGD (3.32) and CED (3.21; p < .05). No effects due to fibre were reported on the faecal hairball variables, with the exception of less total hair weight and hair clumps per gram of dry faeces for cats fed Miscanthus grass (MGH) compared with control diet (COH; p < .05). In conclusion, Miscanthus grass could be used as an alternative ingredient to cellulose in cat diets.