Background: The enamel of permanent teeth forms in well-defined developmental periods and can be used to reconstruct early-life exposures to metals. However, little is known about how consistent metal measurements are when derived from the same tooth. We evaluated the reliability and variability of metal measurements within permanent tooth enamel to aid in its use as a biomarker for metals. Methods: Twenty-two tooth samples (4 incisors, 7 canines, 3 premolars, 4 first or second molars, 4 third molars) from the Metal Exposures and Alzheimer’s Disease Study were analyzed for aluminum (Al), arsenic (As), cadmium (Cd), copper (Cu), iron (Fe), lead (Pb), manganese (Mn), nickel (Ni), and zinc (Zn) using laser ablation inductively coupled plasma mass spectrometry. Up to three laser ablation lines in the enamel were analyzed per tooth. Metal levels were normalized to calcium to account for variability in tooth mineralization and log-transformed due to skewed distributions. Adjusting for tooth type, we calculated the intraclass correlation coefficient (ICC) between ablation lines in enamel capturing overall exposures and the coefficient of variation (CV) across five segments of an ablation line capturing exposures over time. Results: ICCs were greater than 0.70 for most metals: Al (0.73), As (0.99), Fe (0.96), Pb (0.95), Mn (0.85), and Ni (0.90). ICCs were lower for Cd (0.52), Cu (0.61), and Zn (0.44). CVs were highest for Cd (61-154%), between 12-30% for Mn, Ni, As, and Pb, 12-44% for Al and Fe, 35-64% for Cu, and 78-107% for Zn. Conclusions: Repeated measurements of overall exposures in enamel are consistent for most metals. Higher CVs suggest more variation in metal measurements over time. These results can facilitate using permanent teeth as a biomarker for early-life exposures to metals.