Wanlass' departure follows 19 years with the Obie-winning ensemble theatre company. She joined SITI as stage manager in 1995, before becoming managing director and then executive director in 2000.
Wanlass and her family are relocating to the Los Angeles area. She will serve as managing director for Cornerstone Theater Company in California.
During her time with SITI, Wanlass helped to create over 35 productions, which premiered in or toured to 88 cities, 32 states and 19 countries. She also played a significant role in the successful launch of SITI's new year-round conservatory.
"Megan Wanlass has been a close partner and collaborator over the past nineteen years," artistic director Anne Bogart said in a statement. "I am grateful for her vision, creativity, and commitment and I will miss her. But I am also proud of who she has become in the American theater landscape."
SITI's board of directors has launched an international search for a new executive director. Current deputy director Michelle Preston has been appointed interim executive director. Visit siti.org for more information.