βIII-tubulin (TUBB3) expression is associated with therapeutic resistance and aggressive disease in non-small cell lung cancer (NSCLC), but the basis for its pathogenic influence is not understood. Functional and differential proteomics revealed that βIII-tubulin regulates expression of proteins associated with malignant growth and metastases. In particular, the adhesion-associated tumor suppressor maspin was differentially regulated by βIII-tubulin. Functionally, βIII-tubulin suppression altered cell morphology, reduced tumor spheroid outgrowth and increased sensitivity to anoikis. Mechanistically, the PTEN/AKT signaling axis was defined as a critical pathway regulated by βIII-tubulin in NSCLC cells. βIII-tubulin blockage in vivo reduced tumor incidence and growth. Overall, our findings revealed how βIII-tubulin influences tumor growth in NSCLC, defining new biological functions and mechanism of action of βIII-tubulin in tumorigenesis.