Abstract Aims We investigated the clinical implications and molecular features of TLS in stage I lung adenocarcinoma (LUAD). Methods We retrospectively reviewed the clinicopathological characteristics of 540 patients with p‐stage I LUAD. Logistic regression analysis was applied to determining the relationships between clinicopathological features and the presence of TLS. TLS‐associated immune infiltration pattern and signature genes were characterized using the transcriptomic profiles of 511 LUADs from The Cancer Genome Atlas (TCGA) database. Results The presence of TLS was associated with a higher pT stage, low‐ and middle‐grade patterns, and the absence of tumor spreading through air spaces (STAS) and subsolid nodules. Multivariate Cox regression analysis identified that the presence of TLS was associated with favorable overall survival (OS) (p