Spruce galactoglucomannan is a wood-derived polysaccharide of modest molar mass that has recently been made available in kg-scale for research and development of value-added products. To promote the application of spruce galactoglucomannans in, for example, food applications, it is vital to understand also the rheological behaviour of the mixtures of galactoglucomannans with other polysaccharides. Rheological measurements were applied to study the rheological properties of mixtures of spruce galactoglucomannans and high-molar-mass konjac glucomannan, xanthan, guar gum, locust bean gum, and carrageenan. Shear rate-dependence of viscosity and applicability of the Cox-Merz relationship of mixtures of spruce galactoglucomannans with the other polysaccharides were studied. Spray-dried and ethanol-precipitated galactoglucomannans were also prepared for comparison. The effects of polysaccharide mixture ratio, temperature, ionic strength, and deacetylation were discussed. Mixtures of spray-dried galactoglucomannans and konjac glucomannan showed lower elastic properties than that of ethanol precipitated galactoglucomannans and konjac glucomannan. The viscoelastic spectra of mixtures of both galactoglucomannans and deacetylated galactoglucomannans with konjac glucomannan obtained temperature dependency throughout the cooling process. Ionic strength had an effect on the rheological properties of mixtures of galactoglucomannans with konjac glucomannan. Deacetylation of galactoglucomannans did not affect the viscoelastic spectra significantly.