(1) Objectives: This study aims to determine the effectiveness of mindfulness–integrated cognitive behavior therapy on executive function and psychological symptoms in patients with multiple sclerosis in Shiraz. (2) Design: The general design of this study is experimental pre-test and post-test. (3) Setting and conduct: Fifty patients with MS who are eligible for inclusion and exclusion criteria are selected by convenient sampling and are randomly assigned in two groups (MICBT and UC). Participants of both groups fill out Trail Making Test (TMT), Cognitive Abilities Questionnaire and the Depression Anxiety and Stress Scale (DASS-21) as pre-test and post-test. The data will be analyzed by SPSS-18, using the Multivariate Analysis of Covariance (MANCOVA). (4) Participants including major eligibility criteria: Inclusion criteria are patients with the diagnosis of multiple sclerosis by a neurologist; aged 20-45 years; female and exclusion criteria are a history of substance abuse; a history of receiving psychological interventions during the past month. (5) Interventions: The intervention consists of 8 sessions (each session is 90 minutes) of mindfulness–integrated cognitive behavior therapy in conjunction with the routine pharmacotherapy of the disease for the experimental group while control group only receives the routine drug therapy. (6) Main outcome measures: Main outcome measures variables are executive function and psychological symptoms.