The background of this research began with an apprehension of the need for students' learning in accordance with their learning abilities relating to the application of a flipped classroom model in the Biology class of XYZ Senior High School. Preliminary research showed the different needs of individual students; thus, differentiated learning was required especially in the face-to-face meeting in class. Differentiated learning aims to facilitate the different needs of the students based on the level of readiness, learning style preference, and interest. This research aimed at improving the students' learning and its impact on students' cognitive learning outcomes, problem-solving skills development, and learning motivation through the differentiated flipped classroom. The method used in this research was Classroom Action Research. The data were collected through observation, interviews, questionnaires, and evaluation of assessment results based on rubrics and marking schemes. All three variables are measured using rubrics separated from each other. These data are analyzed qualitatively and given a score in quantitative values. In three cycles of action research, the students' learning outcomes cognitively showed a significant increase from the first cycle to the second cycle. From the second cycle to the third cycle, there was a decrease but the decline was not significant. The problem-solving skills increase from the first cycle to the second cycle. In the third cycle, there was an increase until it reached the specified success indicator. In each cycle, the motivation did not increase significantly and tended to be stable but the Attention-Relevance-Confident-Satisfaction (ARCS) motivation model had reached the indicators of the success of the study. The conclusions of this research indicated improvements in the students' problem-solving skills, a high average in motivation indicators, and a significant improvement in cognitive learning outcomes.