The present study was conducted to know the effectiveness of Acceptance and Commitment Therapy on cognitive flexibility and cognitive emotion regulation in anxious female students. The research methodology was semi-experimental with pre-test and post-test design with a control group. The statistical population included all female students studying in the high schools of Bushehr province during the years 2022-2023 which was more than 700 students. The research sample included 30 students diagnosed as anxious using Beck's anxiety questionnaire (anxiety score 16 to 63) and randomly assigned to an experimental group (15) and a control group (15). The experimental group received the acceptance and commitment therapy protocol in 8 sessions (each session 90 minutes), while the control group did not receive any intervention. Research tools included cognitive flexibility inventory and cognitive emotion regulation questionnaire, used for both the experimental and control groups. The data were analyzed using multivariate and univariate covariance by using SPSS26. The research findings showed that acceptance and commitment Therapy has a positive effect on cognitive flexibility and its subscales (alternatives and control), positive strategies for cognitive emotion regulation, and a negative effect on negative strategies for cognitive emotion regulation (p<0.001).