It is believed shots were fired from a moving car in Magpie Close, Forest Gate, at about 13:50 GMT on Friday.
Officers from the Metropolitan Police's Trident unit that tackles gang crime are investigating.
No-one has been arrested but terrorism is not suspected. Anyone with information can contact Crimestoppers anonymously or call police.
A man is in a critical condition and four other people have been injured in a drive-by shooting in east London.