Thea Queen's loft is a loft originally owned by Thea Queen before being passed on to Oliver Queen and Felicity Smoak after their return to Star City. It is now used as office space for Felicity's company, Helix Dynamics. It is located in Star City.
When Thea Queen returned from Corto Maltese she bought the loft with Malcolm Merlyn's money. Oliver disagreed that she used his money and was unaware that Thea and Malcolm were close. After a discussion he agreed with her as she told him she could do good with his money. The two decided to live together in the loft like they used to in the Queen Mansion. While Oliver, as the Arrow, suspected Malcolm for killing Sara Lance he broke through the window as Thea was decorating the Christmas tree, to interrogate her for Malcolm's location. She feigned being scared and then threw glass in his face. Due to Oliver's unwillingness to harm Thea, she was able to escape by jumping from the broken window.
Oliver brought Malcolm to Thea's loft as the latter was severely injured during his imprisonment at Nanda Parbat and needed a place to rest for recovery; Thea wasn't happy with the situation but tolerated her father's stay due to circumstances.
Later, the police were searching for evidence that Oliver is the Arrow, after Ra's al Ghul told Quentin that the latter is the Arrow, after Roy Harper took the blame of being the Arrow, the entire time and faked his death, Oliver was exonerated, after this Ra's attack Thea and mortally wounded her, in order to force Oliver to finally accept his offer to become his successor.
When Vandal Savage attacked Kendra Saunders in Central City, Team Flash brought Kendra to Star City for safety. Oliver and Felicity Smoak invited Barry Allen, Cisco Ramon, and Kendra to the loft for drinks. After visiting with each other and a toast, Vandal Savage broke through the loft window and attacked the group. Barry caught Savage's throwing knives while Oliver engaged him in hand-to-hand combat. Oliver and Thea drove him back with a barrage of arrows with Thea delivering an arrow sending him out of the loft window. However, Oliver and Thea went over to the window to find Savage's body only to see that Savage was nowhere in sight, having survived the fall and escaped.
After a reconnaissance ship from the Dominators landed in Central City, Barry ran to Star City and sped Oliver and John back to the loft where he recruited them, Felicity, and Thea to help battle the aliens.