Shamrock Hotel, Hotel skyscraper in Houston, Texas

The Shamrock Hotel is an 18-story skyscraper in Houston with a green tile roof and over 1,100 guest rooms. It housed multiple restaurants and stood near the Texas Medical Center.

Construction ran from 1946 to 1949 for wildcatter Glenn McCarthy, who built the largest hotel in the United States during the 1940s. It opened on St. Patrick's Day 1949 with fireworks; 2,000 guests paid $42 each for a party costing about one million dollars, attended by over 150 Hollywood celebrities including Errol Flynn and Ginger Rogers. Sold to Hilton Hotels in 1955, it operated as the Shamrock Hilton until Hilton donated it to the Texas Medical Center in 1985; it was demolished on June 1, 1987.

The name comes from the Irish shamrock, and McCarthy ordered furnishings and decor in 63 shades of green as a nod to his ancestral Ireland. The opening on St. Patrick's Day 1949 matched that theme, with fireworks and a party the Houston Chronicle's society editor called "bedlam in diamonds".

Nothing of the hotel remains: it was demolished on June 1, 1987, so there is no building to visit. The site at the southwest corner of Main Street and West Holcombe Boulevard now holds the Texas A&M Institute of Biosciences and Technology and DeBakey High School for the Health Professions, beside the Texas Medical Center. The location is about three miles southwest of downtown Houston.

The pool measured 165 by 142 feet and was billed as the world's largest outdoor pool; it had a three-story diving platform reached by an open spiral staircase. The hotel's north wing held a 1,000-car garage and a 25,000-square-foot exhibition hall.