As a Hong Kong taxpayer, you may claim dependent brother or dependent sister allowance if, during a year of assessment, you or your spouse maintains an unmarried brother or sister who is under 18 years old; or if over 18 years old and under 25 years old: a full-time student; or if over 18 years old: disabled for work.

No double allowance for maintaining the same child is allowed. In other words, if child allowance is claimed by a child’s parent, no dependent brother or dependent sister allowance will be granted in respect of that child in the same year of assessment.

In addition, you may claim Disabled Dependant Allowance in respect of your or your spouse disabled brother or sister. The condition for the claim is that the brother or sister must be eligible to claim an allowance under the Government’s Disability Allowance Scheme from Social Welfare Department.

You may claim dependent brother or dependent sister allowance by completing Part 9 of your tax return for the relevant year of assessment. If you forget to do so, you may still make a claim within the prescribed time limit, i.e. within 6 years after the end of the year of assessment or within 6 months after the issue of a notice of assessment for the year of assessment, whichever is the later. You also need to state details of the omission and submit sufficient evidence to substantiate the claim.

Sources：Hong Kong Inland Revenue Department’s websites

- https://www.gov.hk/en/residents/taxes/salaries/allowances/allowances/allowances.htm
- https://www.ird.gov.hk/eng/faq/all.htm#q34
- https://www.ird.gov.hk/eng/faq/ctr.htm