强直性脊柱炎（拉丁文：spondylitis ankylosans，其中spondylitis原为希腊文脊柱炎之意，ankylosans原系希腊文强直之意），又称僵直性脊椎炎，是一种慢性关节炎，伴随有脊柱关节的疼痛和强直症状。在欧陆亦称此病为白赫铁列夫症（Morbus Bechterew）、白赫铁列夫-史特林佩尔-玛丽症（Bechterew-Struempell-Marie-Krankheit）等。英文为Ankylosing Spondylitis，国际简称为AS.

强直性脊柱炎属于脊柱关节症候群，主要影响腰椎、胸椎以及骶髂关节，现在相信与免疫失调及遗传因子有关。病情发展到最后脊柱关节会成为“竹节样脊柱”，完全僵化，无法弯曲。目前尚无治愈的方法，治疗仅能缓解症状和疼痛。

Ankylosing spondylitis (AS, from Greek ankylos, crooked; spondylos, vertebra; -itis, inflammation), previously known as Bekhterev's disease and Marie-Strümpell disease, is a chronic inflammatory autoimmune disease of the axial skeleton, with variable involvement of peripheral joints and nonarticular structures. AS is one of the seronegative spondyloarthropathies and has a strong genetic predisposition. It mainly affects joints in the spine and the sacroiliac joint in the pelvis. In severe cases, complete fusion and rigidity of the spine can occur.