A calculation of Landau levels and microwave‐induced transition probabilities in the valence band of Si has been performed for the case of the wave vector component along B different from zero. This calculation allows one to compute microwave absorption spectra corresponding to actual experimental conditions. A comparison between the calculated spectra and experimentally observed cyclotron resonance spectra at 45 GHz and 2 K in high‐purity (3900 Ωcm) p‐type Si samples yields an estimate of the five band parameters γ1, γ2, γ3, ϰ, and q. The content of this paper will be restricted to the case of B parallel to the symmetry directions [001], [111], and [110].