Background Lung cancer is the leading cause of cancer-related mortality worldwide. Sarcopenia, defined as the loss of muscle mass and function, is known to cause adverse health outcomes. The purpose of this umbrella review was to integrate published systematic reviews and meta-analyses exploring sarcopenia and lung cancer to provide comprehensive knowledge on their relationship. Methods Eligible studies were searched from scientific databases until June 28, 2022. Critical appraisal was performed using A Measurement Tool to Assess Systematic Reviews (AMSTAR) 2. The impact of sarcopenia on the pathophysiology, prevalence, and prognosis of lung cancer is summarized at the level of systematic reviews or meta-analyses. Results Fourteen reviews and meta-analyses were conducted. The methodological quality was high for one review, low for nine, and critically low for four. The most common standard for diagnosing sarcopenia in the lung cancer population is computed tomography (CT) to measure the skeletal muscle index at the third lumbar vertebra (L3). Sarcopenia was highly prevalent among patients with lung cancer, with a pooled prevalence ranging from 42.8% to 45.0%. The association between sarcopenia and increased postoperative complications and decreased disease control rates with immune checkpoint inhibitors has been demonstrated. Mortality was significantly higher in sarcopenic patients than in non-sarcopenic patients with lung cancer, regardless of the stage of disease or type of treatment. Conclusions Sarcopenia is a poor prognostic factor for lung cancer. Future studies are necessary to clarify the pathophysiology of sarcopenia and develop effective interventions for sarcopenia in patients with lung cancer.