The European Organisation for Research and Treatment of Cancer (EORTC) Quality of Life Questionnaire-Lung Cancer 13 (QLQ-LC13) covers 13 typical symptoms of lung cancer patients and was the first module developed in conjunction with the EORTC core quality-of-life (QL) questionnaire. This review investigates how the module has been used and reported in cancer clinical trials in the 20 years since its publication. Thirty-six databases were searched with a prespecified algorithm. This search plus an additional hand search generated 770 hits, 240 of which were clinical studies. Two raters extracted data using a coding scheme. Analyses focused on the randomized controlled trials (RCTs). Of the 240 clinical studies that were identified using the LC13, 109 (45%) were RCTs. More than half of the RCTs were phase 3 trials (n = 58). Twenty RCTs considered QL as the primary endpoint, and 68 considered it as a secondary endpoint. QL results were addressed in the results section of the article (n = 89) or in the abstract (n = 92); and, in half of the articles, QL results were presented in the form of tables (n = 53) or figures (n = 43). Furthermore, QL results had an impact on the evaluation of the therapy that could be clearly demonstrated in the 47 RCTs that yielded QL differences between treatment and control groups. The EORTC QLQ-LC13 fulfilled its mission to be used as a standard instrument in lung cancer clinical trials. An update of the LC13 is underway to keep up with new therapeutic trends and to ensure optimized and relevant QL assessment in future trials.