KRAS belongs to the RAS family of oncogenes. KRAS mutations are detected in approximately 20% to 25% of lung adenocarcinoma. Contrary to most other oncogenic driver mutations, KRAS is more often found in smokers and is detected at lower frequency in East Asian patient cohorts. Mutations in KRAS are usually mutually exclusive with other oncogenic driver aberrations including EGFR, BRAF, HER2 mutations and ALK and ROS1 rearrangements. KRAS mutations in NSCLC most often occur in codons 12 or 13 and with a lower frequency in codon 61. The prognostic as well as predictive role of KRAS mutations continues to be studied. Although various attempts inhibiting KRAS have been made, there is no established therapy specific for this large patient subpopulation.