Background context Concurrent ossification of the ligamentum flavum (OLF) in the cervical, thoracic, and lumbar spine is a rare occurrence often associated with rheumatologic abnormalities. Although the pathology may be asymptomatic and discovered incidentally on routine imaging, compression of the cord and surrounding nerve roots can produce myelopathic or radiculopathic symptoms that are best treated with surgical decompression. There is limited evidence to support the use of single versus multistage decompression for tandem ossification at multiple levels, although several factors including duration of symptoms have been associated with a worse prognosis. Purpose To describe the presence of extensive symptomatic tandem OLF with concurrent ossification of the posterior longitudinal ligament (PLL) and its treatment using multistage decompression. Study design Case report and literature review. Methods The authors describe a case of a 35-year-old woman with OLF extending from the cervical to lumbar spine and tandem ossification of the cervical PLL. Her initial presentation was significant for symptoms consistent with thoracic myelopathy in the absence of radiculopathic findings, and initial imaging also demonstrated disc herniation at L4-L5 and L5-S1. Results The patient was first treated with a thoracic laminectomy and fusion from T7 to T11, given her back pain and thoracic myelopathy. Persistence of myelopathic symptoms necessitated further surgical intervention with a posterior cervical decompression and fusion from C3 to T1. Finally, after the appearance of radiculopathic findings, she underwent a microscopic L4-L5 laminectomy with improvements in her symptoms and ambulation. Conclusions Symptomatic OLF in non-East Asian population is a rare occurrence. Its etiology is likely multifactorial, involving both biomechanical and genetic factors. Although early detection and management are necessary, multistage decompression can be an effective intervention for extensive multilevel ossification.