"They will be attending Malia's high school graduation ceremony in Washington, DC," said spokeswoman Jen Friedman.
Instead, a close aide "will read a letter from the president and the first lady as part of Friday's service in Louisville."
Legendary former heavyweight boxing champion Muhammad Ali breathed his last on June 4.
74-year-old Ali, the greatest boxers of all time, was hospitalised following respiratory problems.
Ali's fame transcended sport during a remarkable heavyweight boxing career that spanned three decades. Ali, who suffered from Parkinson's disease for decades, spent most of his time in recent years at his residence because city's warm climate made it easier for him to manage the illness.