The quality properties of biscuits with partial replacement of sugar by inulin (at 0, 10, 20 and 30%) and wheat flour by barley flour (at 0, 10, 20, 30 and 40%) were studied. A commercial and a jet milled finer barley flour were used. For all flour substitutions, elevated amounts of inulin led to increased weight and decreased spread ratio of the biscuits. Inulin biscuits, within the same flour composition, were softer than those with no inulin but inulin’s concentration was not statistically important. The incorporation of barley flour resulted in reduced lightness, more evident in the case of the finer barley flour. Inulin also affected the lightness of the biscuits. Phenolic content was affected by the presence of barley flour but no clear trend of inulin’s effect was detected. The interactions between barley substitution, inulin substitution and particle size of the barley flour were important for all studied properties, i.e., weight, spread ratio, hardness, total phenolic content and color.