"Las' time I saw you, you was only a baby. Yeh look a lot like yer dad, but yeh've got yer mum's eyes."
—Rubeus Hagrid to the eleven-year-old Harry Potter.
Harry is a near-spitting image of his father, having untidy jet black hair, but his brilliant green, almond-shaped eyes are identical to those of his mother. Harry's physique as a boy was described as "small and skinny," with a thin face and knobbly knees, due to his poor quality of life in his childhood. When he was almost eighteen, he was "within an inch" of his father's height, and James was often described as tall. It is likely that as he aged further he would eventually grow as tall or taller than his father. Harry wears round-rimmed glasses, peculiarly similar to his father's glasses.
Upon Harry's forehead, covered by his unruly black hair, is a scar shaped like a lightning bolt. The scar is a result of the failed (and famed) Killing Curse cast on him by Lord Voldemort when he was an infant. It burned painfully whenever Voldemort was near Harry or feeling particularly strong emotions, but this stopped after Voldemort's death.
Harry has also a faint scar on the back of his right hand which says "I must not tell lies." This scar was caused while Harry spent detentions with Dolores Umbridge, who forced him to use a quill that carved the words into the back of his hand.
When possessed by Lord Voldemort at the end of the Battle of the Department of Mysteries, Harry's eyes become somewhat glassy green in appearance.