Multiple sclerosis (MS) is a chronic debilitating disease. MS is associated with high rates of depression and dissatisfaction with life. “Positive psychology,” (PoP) has endeavored to better understand happiness, meaning in life and how these can be developed. There is a growing interest amongst clinicians and consumers in happiness and personal growth as indicators of patients’ well-being. To evaluate happiness and personal growth in treated relapsing-remitting (RR) MS patients compared with age and gender matched healthy subjects. The Oxford Happiness Inventory (OHI), the Satisfaction with Life Scale (SLS) and the Personal Growth Initiative Scale (PGIS) were completed by 105 RR-MS patients [70 females, mean age 44.4 ± 13.3 years, Expanded Disability Status Scale (EDSS) 3.6 ± 2.3] and 87 healthy subjects (66 females, mean age 39.7 ± 11.5 years). Scores were correlated with disease and treatment related parameters. All patients were treated for at least 6 months with interferon-beta-1a (Rebif). Mean happiness scores in MS patients for the OHI (103.1 ± 17.0), the SLS (23.9 ± 6.8) and the PGIS (40.1 ± 7.6) were not statistically different from those of healthy subjects. Categorical analysis of the SLS demonstrated a different distribution wherein more MS patients were in the “dissatisfied” subgroup (SLS score < 20) as compared to healthy subjects (24.8% vs. 12.6%, p = 0.045), while rates were similar in the extremely satisfied subgroup (SLS ≥ 30). Happiness was scored similarly in treated RR-MS patients and healthy subjects despite a greater percentage of patients reporting being dissatisfied with their lives. These findings may reflect positive treatment effects, hedonic adaptation or their combination.