The fire broke out around 4:30am Saturday at an independently-owned, 12-stall barn with stalls for rent in the 2800 block of Spears Road at Walters Road.
While firefighters were able to rescue several horses, they were not able to save them all.
The horse owners have been near the damaged barn all day, hoping to get some answers.
Investigators say they don't have many clues on what started the deadly blaze.
"It's a phone call everyone dreads to hear," horse owner Patrick McKenzie said.
McKenzie kept his horse "Classy" at the stable. He learned she's among the 11 that died there as one of the barns collapsed from flames.
Four other horses were rescued as the fire continued spreading.
"You wake up in the morning to find out something that you love burned. It's a horrible way to go," McKenzie said.
Investigators say a total of 40 horses were being housed in five barns on the property.
A large barn with 12 stables was already fully involved when firefighters with the Little York Fire Department got to the scene, and flames were quickly spreading toward the other buildings.
"The barn had already collapsed, and firefighters were faced with having to remove some heavy metal roofing structure from the top of the barn in order to fight the fire," said Mitchell Weston with the Harris County Fire Marshal's Office.
As Little York firefighters tackled the charred debris, worried horse owners gathered nearby, watching and wondering exactly what happened.
"We don't have any reason to believe [there was] anything suspicious or foul play at this time," Weston said.
For now, the upset horse owners say they just want some answers.
"Hopefully, we'll just move on from here," McKenzie said.
The investigation into this fire is ongoing.
Veterinarians are keeping a close eye on one of the rescued horses because it suffered severe burns.