Family members are critical mediators of the experiences of transgender people. We studied whether transgen-der subjects had disclosed their identity to their families and their families’ reactions after the disclosure. We also evaluated the subjects’ mental state and its association with disclosure status. Transgender people were recruited for this anonymous questionnaire survey in the Okayama University Hospital gender clinic. Subjects disclosed their identity to family members at the following rates: 68.7% to the father, 89.1% to the mother, 59.1% to a brother, 77.8% to a sister, and 47.6% to grandparents. Fathers had the lowest rate (26.7%) of posi-tive reactions, while over 50% of fathers showed an ambiguous response. Approximately 20% of parents showed a negative response. The majority of parents agreed to hormonal treatment and sex-reassignment sur-gery and that the transgender child should live with the gender they wanted to express. However, the rate of subjects with mood and anxiety disorders according to the Kessler 6 scale was significantly higher in those who experienced negative or ambiguous reactions from family members compared to those who experienced posi-tive reactions. Educational and mental health professionals should support the disclosure process of transgen-der people as well as their family members