Feeding assistance should be safe and improve the assisted individual's ability to feed, yet objective tools for evaluating these skills are lacking. This study focuses on developing a tool for assessing feeding assistance skills. A group consisting of 25 experts employed the Delphi method to achieve a consensus on the essential items necessary for assessing feeding assistance skills. Subsequently, a draft score using a three-point scale was developed. To test the reliability of the draft scores, a group of 20 patients and 20 nurses was matched to record a meal assistance scene, which were independently evaluated by three raters. We computed the AC1 statistic to assess both intra- and inter-rater reliability, and further examined correlations between the Feeding Assistance Skill Score (FASS) scores and outcome items to verify validity. Initially, an 18-item draft score was generated using the Delphi method. Subsequently, seven items were omitted from the intra- or inter-rater reliability analysis. Furthermore, after discussion, researchers removed one item that assessed food cognition, because the agreement score between the two items was 91%. Finally, the 10-item FASS was developed, showing a correlation with dietary intake upon validation. We successfully developed a scoring system for peer evaluation of feeding assistance skills. Future studies should aim to validate the FASS. The implementation of the FASS aims to assess the effectiveness of feeding assistance training and care quality, potentially improving safety and satisfaction for those receiving feeding assistance.