Introduction: Demirjian’s and Willems’ methods have been studied in different juvenile populations to assess their accuracy and suitability for each population in chronological age estimation. The Willems method seems to be more suitable for age estimation in different populations when compared to the Demirjian method, which, despite this, is still the most widely used. However, to date, there are no studies on the Portuguese population to address this question. Objectives: Evaluate the differences in chronological age estimation with Demirjian’s and Willems’ dental methods to determine which is the most suitable for the Portuguese population. Material and Methods: In 120 orthopantomograms of Portuguese individuals, 64 females, 56 males, aged between 6 and 16 years, the maturation stage of the first 7 teeth of the third quadrant was classified and Demirjian’s and Willems’ methods were applied. Results: In males, both methods overestimated age, with statistically significant differences between estimated age and chronological age. In females, the Demirjian method overestimated age, and the difference was statistically significant. Willems’ method underestimated age, without statistical significance. Conclusions: While in males there seems to be no difference regarding the choice of an age estimation method, in females the use of the Willems method should be preferred.