Background and purpose: The treatment landscape for patients with advanced non-small cell lung cancer (NSCLC) has evolved significantly since the introduction of immunotherapies. We here describe PD-L1 testing rates, treatment patterns, and real-world outcomes for PD-(L)1 inhibitors in Sweden. Materials and methods: Data were obtained from the Swedish National Lung Cancer Registry for patients with advanced NSCLC and Eastern Cooperative Oncology Group (ECOG) performance status (PS) 0–2 who initiated first-line systemic treatment from 01 April 2017 to 30 June 2020. PD-L1 testing was available in the registry from 01 January 2018. Kaplan-Meier was used for overall survival (OS) by type treatment and histology. Results: A total of 2,204 patients with pathologically confirmed unresectable stage IIIB/C or IV NSCLC initiated first-line treatment, 1,807 (82%) with nonsquamous (NSQ) and 397 (18%) with SQ. Eighty-six per cent (NSQ) or 85% (SQ) had been tested for PD-L1 expression, a proportion that increased over time. The use of platinum-based therapy as first-line treatment decreased substantially over time while there was an upward trend for PD-(L)1-based therapy. Among patients with PS 0–1 initiating a first-line PD-(L)1 inhibitor monotherapy, the median OS was 18.6 and 13.3 months for NSQ and SQ NSCLC patients, respectively, while for the PD-(L)1 inhibitor and chemotherapy combination regi-men, the median OS was 24.0 months for NSQ and not evaluable for SQ patients. Interpretation: The majority of advanced NSCLCs in Sweden were tested for PD-L1 expression. Real-world OS in patients with PS 0–1 receiving first-line PD-(L)1 inhibitor-based regimens was similar to what has been reported in pivotal clinical trials on PD-(L)1 inhibitors. © 2024 The Author(s).