The two were married Sunday in front of 200 guests at Lauren's 17,000-acre Double RL Ranch in the Rocky Mountains, People reported.
The bride's dress was designed by her father-in-law, who also created a bridal gown for his own daughter, Dylan Lauren, owner of Dylan's Candy Bar, earlier this year.
The theme of the wedding melded the two families' fashion sensibilities with a dress code of "black tie with a Western twist."
Wedding attendees included Bush's uncle, former President George W. Bush, and first lady Laura Bush, along with Jenna and Barbara Bush and former Florida Gov. Jeb Bush. Her grandparents, former President George H.W. and first lady Barbara Bush, were unable to attend, but sent the couple a video message.
Dylan Lauren and Ivanka Trump were also in attendance.
The bride, who reportedly will take the name Lauren Bush-Lauren, was walked down the aisle by her father, Neil, and mother Sharon.