Importance: Anlotinib is a novel multitarget tyrosine kinase inhibitor for tumor angiogenesis and proliferative signaling. A phase 2 trial showed anlotinib to improve progression-free survival with a potential benefit of overall survival, leading to the phase 3 trial to confirm the drug's efficacy in advanced non-small cell lung cancer (NSCLC). Objective: To investigate the efficacy of anlotinib on overall survival of patients with advanced NSCLC progressing after second-line or further treatment. Design, Setting, and Participants: The ALTER 0303 trial was a multicenter, double-blind, phase 3 randomized clinical trial designed to evaluate the efficacy and safety of anlotinib in patients with advanced NSCLC. Patients from 31 grade-A tertiary hospitals in China were enrolled between March 1, 2015, and August 31, 2016. Those aged 18 to 75 years who had histologically or cytologically confirmed NSCLC were eligible (n = 606), and those who had centrally located squamous cell carcinoma with cavitary features or brain metastases that were uncontrolled or controlled for less than 2 months were excluded. Patients (n = 440) were randomly assigned in a 2-to-1 ratio to receive either 12 mg/d of anlotinib or a matched placebo. All cases were treated with study drugs at least once in accordance with the intention-to-treat principle. Main Outcomes and Measures: The primary end point was overall survival. The secondary end points were progression-free survival, objective response rate, disease control rate, quality of life, and safety. Results: In total, 439 patients were randomized, 296 to the anlotinib group (106 [36.1%] were female and 188 [64.0%] were male, with a mean [SD] age of 57.9 [9.1] years) and 143 to the placebo group (46 [32.2%] were female and 97 [67.8%] were male, with a mean [SD] age of 56.8 [9.1] years). Overall survival was significantly longer in the anlotinib group (median, 9.6 months; 95% CI, 8.2-10.6) than the placebo group (median, 6.3 months; 95% CI, 5.0-8.1), with a hazard ratio (HR) of 0.68 (95% CI, 0.54-0.87; P =.002). A substantial increase in progression-free survival was noted in the anlotinib group compared with the placebo group (median, 5.4 months [95% CI, 4.4-5.6] vs 1.4 months [95% CI, 1.1-1.5]; HR, 0.25 [95% CI, 0.19-0.31]; P <.001). Considerable improvement in objective response rate and disease control rate was observed in the anlotinib group over the placebo group. The most common grade 3 or higher adverse events in the anlotinib arm were hypertension and hyponatremia. Conclusions and Relevance: Among the Chinese patients in this trial, anlotinib appears to lead to prolonged overall survival and progression-free survival. This finding suggests that anlotinib is well tolerated and is a potential third-line or further therapy for patients with advanced NSCLC. Trial Registration: ClinicalTrials.gov identifier: NCT02388919.