Objectives: This controlled cross-sectional study investigated the prevalence of different types of parentification in women with fibromyalgia (FM) compared to women with rheumatoid arthritis (RA), healthy controls (HC) and women with depression or anxiety disorder (AD). The study also examined associations with maladaptive interpersonal styles (subjugation, approval seeking, and self-sacrifice). Method: Validated self-report questionnaires were completed by 202 female FM patients, 51 women with RA, 41 with AD and 119 HC. Results: Women with FM reported significantly higher levels of all parentification variables compared to the RA and HC groups but not compared to the AD group. An interaction effect with educational level was observed: among participants with Master’s degree, some parentification scores (specifically unfairness, parent focused and emotional caregiving) were more pronounced in the FM group than in the AD group. Significant correlations were also found between parentification and maladaptive interpersonal styles. Conclusions: These findings confirm a higher prevalence of fibromyalgia, depression, and anxiety disorder among women with parentification, as well as a link with maladaptive interpersonal styles. Educational level appears to play a moderating role, but these interactions should further be examined in larger groups. The results underscore the importance of a personalized biopsychosocial approach in fibromyalgia alongside standard therapy and highlight the value of early identification of risk factors.