The purposes of this study was to investigate: (1) group differences on parentification; (2) correlation between parentification and health; (3) correlation between parentification and self-differentiation; (4) correlation between self-differentiation and health; and (5) correlation among parentification, self-differentiation, and health. The samples comprised of 423 senior high and vocational high school students from six areas across Taiwan. Instruments used in this study included “Parentification Scale”, “Self-Differentiation Questionnaire”, and “General Health Scale”. The main findings are as follows: (1) No significant gender difference of parentification was found; “instrumental caregiving” was significantly different among groups of different birth order; “unfairness” was significantly different among groups of different parental marital status. (2) Parentification is significantly correlated with health. (3) Parentification is significantly associated with self-differentiation; (4) Self-differentiation are significantly correlated with health; and (5) Parentification, self-differentiation are significantly correlated with health. Implications of the results for counseling and parent education as well as suggestions for future research are proposed.