Let k be a commutative ring containing 1 2 . In this paper, we construct certain homotopy fibration sequences for Grothendieck-Witt spectra of smooth quadric hypersurfaces over k. As an application, we compute Witt groups of smooth quadric hypersurfaces over certain kinds of bases. Contents 1. Introduction 1 2. Review: Grothendieck-Witt theory 4 3. Review: Semi-orthogonal decomposition on D b Q 8 4. The canonical involution 11 5. Grothendieck-Witt spectra of odd dimensional quadrics 13 6. Witt groups of odd dimensional quadrics 18 7. An exact sequence 21 8. Grothendieck-Witt spectra of even dimensional quadrics 22 9. Witt groups of even dimensional quadrics 26 10. Witt groups of Quadrics defined by m⟨−1⟩ ⊥ n⟨1⟩ 29 Appendix A. Witt groups of Clifford algebras 32 References 34