Meghan’s visit was unannounced and came as the community still reels from the mass shooting committed by 18-year-old Salvador Ramos on Tuesday.
A spokesperson for the duchess said she took the trip in a personal capacity as a mother to offer her condolences and in-person support to a community in grief.
Meghan, who lives in California, was not accompanied by husband Harry during her visit to the memorial on Thursday.
She was wearing a baseball cap, T-shirt, jeans and trainers.
Meghan was also pictured looking down at the white crosses bearing the names of those who lost their lives to the gunman’s rampage at Robb Elementary School in the small town of Uvalde.
She laid her flowers near the cross of 10-year-old Uziyah Garcia, which had the words “you will be missed” written on it, according to the Los Angeles Times.
It came as law enforcement authorities faced mounting questions and criticism over how long it took them to storm the school and put a stop to the rampage.
The motive for what was America’s deadliest mass shooting in a decade remains under investigation, with authorities saying Ramos had no known criminal or mental health history.
Witnesses told how frustrated onlookers urged police to charge into the school during the siege which was eventually brought to an end when a US Border Patrol team did just that and shot the gunman to death.
“Go in there! Go in there!” women shouted at the officers soon after the attack began, according to Juan Carranza, 24, who watched the scene from outside a house across the street.
Mr Carranza said the officers should have entered the school sooner. “There were more of them. There was just one of him.”
Up to an hour elapsed from when Ramos opened fire on the school security officer to when the tactical team shot him, according to Texas Department of Public Safety Director Steve McCraw.
Two teachers also died in the attack.