The Higgs has turned out to be "light", whose mass being of the order of the weak scale. This suggests that the Higgs self-coupling is governed by gauge principle. As an attractive candidate of BSM having such property, we discuss gauge-Higgs unification (GHU) scenario. We demonstrate that, just as in MSSM, the Higgs mass is predictable as a UV-finite value even after the quantum correction in GHU. The model we take is 6D GHU with a suitable orbifolding, which predicts M_H = 2M_W at the tree level. We also point out Higgs interactions, such as Yukawa interaction, in the GHU (and related scenario of dimensional deconstruction), show characteristic "anomalous" behavior, i.e. the deviation from the predictions of the SM