Background. Dental students learn and practice clinical procedures in clinical skills laboratories. These practices are graded by qualified staff to evaluate the effectiveness of their learning. Valid evaluation requires accuracy and reliability. Although a well-developed checklist for preclinical skill evaluation exists in theory, it is challenging to implement in practice. This study was undertaken to develop and evaluate the reliability of an assessment sheet for all-ceramic crown preparations. Methods. The study consisted of two phases: the development stage and the judgmentquantification stage. Two examiners evaluated all-ceramic crown preparations made by secondyear dental students using the developed assessment sheet to test criterion validity. The final grade was determined based on the number of errors identified using the assessment sheet. The relationship between the negative points and the final grades awarded was determined using Spearman’s correlation. The study calculated the intra- and inter-examiner agreement for two rounds of evaluation, conducted one month apart, using Cohen’s unweighted Kappa test. The study employed the Item-Content Validity Index (I-CVI) to evaluate the content validity for each item and the Scale-Content Validity Index (S-CVI) to assess the content validity of the overall scale used in all-ceramic crown preparation procedures. Results. The assessment sheet developed for all-ceramic crown preparations was reliable, with strong content validity and a significant negative correlation between grades assigned and the number of errors observed. The assessment sheet defined up to three levels of performance for each item, providing a consistent and objective approach to evaluation. The linear regression graph successfully determined the maximum number of acceptable errors and established the minimum passing grade. The inter- and intra-examiner agreement for the two assessment rounds was found to be fair to moderate. Conclusion. The study showed that the developed assessment sheet for all-ceramic crown preparations is reliable and can provide a consistent and objective approach to evaluation. It can benefit both students and instructors. Further research is recommended to evaluate the impact of the developed assessment sheet on students’ learning outcomes.