In this study, we report on the effects of cellulose fibres of different particle size on changes to dough water absorption and rheology; and on effects of fibre on starch and gluten, separately, at different levels of fibre incorporation (0.1–10%). Water absorption and dough-mixing properties were affected with fibre incorporation, with 40-μm fibre incorporation resulting in greater absorption values. Dough stickiness and extensibility were affected by cellulose fibre particle size, and decreased with increasing fibre addition. Flour or starch and fibre mixtures were evaluated using a Micro ViscoAmlyoGraph (MVAG), and the resulting gel firmness was measured using a texture analyzer. MVAG peak and final viscosities of flour samples decreased with increasing fibre content. Starch–fibre interactions followed a similar trend as flour–fibre treatments. Gluten–fibre interactions were also measured using a Gluten Peak Tester on flour–fibre and gluten–fibre mixtures. Cellulose fibre enhanced the kinetics of gluten aggregation.