<p>Lung cancer has a remarkably high global incidence and ranks among the most frequent malignancies, with mortality rates placing it first worldwide. Although lung cancer typically metastasizes to the brain, bone, adrenal glands, and liver, the advent and efficacy of novel treatments such as immunotherapy and tyrosine kinase inhibitors have been associated with an increasing incidence of metastases in atypical sites, including peritoneal involvement in Non-Small Cell Lung Cancer. Adenocarcinoma is the histological subtype most frequently responsible for peritoneal carcinomatosis. Little is known about the underlying pathogenic mechanisms leading to peritoneal implantation, and diagnosis is often delayed until advanced disease stages, as symptoms are frequently nonspecific and may be mistaken for the natural progression of advanced lung cancer under systemic oncological treatment. Diagnosis is primarily clinical when ascites develops, but imaging modalities such as computed tomography and fluorodeoxyglucose positron emission tomography/computed tomography can be highly informative. Cytological and molecular analysis of peritoneal fluid obtained via drainage also contributes to diagnosis. Treatment mainly relies on systemic therapy for lung cancer with peritoneal metastases, while loco-regional interventions are generally reserved for symptom control. Considerable progress is still needed in the prevention, early diagnosis, and optimal management of peritoneal carcinomatosis, and future research, despite the rarity of cases, should focus on these aspects. In this review, we aim to analyze the limited literature currently available and explore future directions in the approach to peritoneal carcinomatosis in Non-Small Cell Lung Cancer.</p>