This study aimed to determine the effectiveness of the 5Ps Authentic Assessment on Normalized Gained Knowledge of grade 9 students. The respondents of the study were the 120 Grade 9 learners in the Division of Cabanatuan City. 20 students per school participated in Camp Tinio National High School, Eastern Cabu National High School, Cesar E. Vergara Memorial High School, Marciano del Rosario National High School, Mayapyap National High School, and San Josef National High School. The respondents were grouped into control and experimental groups. A quasi-experimental research design was used in the study. Both groups took the pre-test and utilized the Self Learning Module. However, the control group was exposed to the 50-item quiz while learners in the experimental group utilized the 5Ps authentic assessment. Pre-test and post-test were used to gauge the respondents improvement in terms of mean scores. Experiences in using the 5Ps authentic assessment were also gathered from the experimental group. T-tests were used to determine if there was a significant difference in the pre-test and post-test scores of the control and experimental groups. The result showed that there was no significant difference in the pre-test scores of the control and experimental groups with 23.92 and 22.17 mean scores respectively. Meanwhile, the post-test mean scores of the control and experimental group were 28.72 and 35.25 respectively, implying that there was a significant difference in post-test mean scores of the control group. There is a positive correlation between profile variables and authentic assessment, except sex. It has the same result in the relationship between profile variables and Normalized gained knowledge. However, the Normalized gained score has a high positive correlation with authentic assessment. The higher the authentic score, the higher the Normalized gained score. This signifies that the 5Ps authentic assessment is an effective teaching aid to get higher Normalized gained knowledge from the least learned topic in Science which is the Non-Mendelian Genetics.