Abstract The effect of epitaxial stress on Jahn–Teller (JT) distortion in epitaxial LaMnO 3 (LMO) films has been investigated. Both 2θ – ω scans and reciprocal space maps (RSMs) indicate that LMO samples are subjected to compressive stress. Obvious Laue oscillations can be detected in 2θ – ω scans, indicating the high quality of samples. RSMs of symmetry peak (001) and asymmetry peak (−103) imply different epitaxial stress for LMO films deposited on different substrates. Raman spectra measurements reveal that the degree of JT distortion can be well tuned via the epitaxial stress which may further influence on the electron localization in the films. This study might benefit to understanding the correlation between crystalline structure and electrical transport properties of LMO films and related LMO-based superlattices.