You can claim a child born anytime in 2023 on your 2023 taxes, assuming they meet all the other dependent qualifications. A baby born in 2024 can be claimed on your 2024 taxes.
When we ask how many months your newborn lived with you, always answer the whole year, even if your baby was born on the last day of 2023. The same holds true for any healthcare coverage questions if your newborn was insured from the date of birth.
