Peter Chou, the previous CEO, will remain with the company, and lead its "Future Development Lab" to identify new growth opportunities, HTC said Friday.
Wang, who was already company chairwoman, had been taking a larger managerial role in the last two years, so that Chou could focus on product development.
On Friday, the board of directors and HTC's executive team agreed to formalize that progression and name Wang as CEO to usher in its next stage of development, the company said.
During Chou's tenure, HTC became a major Android handset maker, but its market share and sales have since declined in the face of fierce competition from Apple, Samsung Electronics, and an emerging crowd of Chinese vendors.
By last year, HTC ranked as only the world's 14th-largest smartphone vendor, said Melissa Chau, an analyst with research firm IDC.
HTC still commands some brand recognition, she said, but its higher-end phones have struggled to stand out when both Apple and Samsung have far larger marketing and research budgets.
At the same time, HTC is facing pressure from the lower end of the market, due to the rise of Chinese vendors offering inexpensive handsets.
Smartphones are increasingly becoming commodities, so companies have to rely on their brand or software to lock users in, Chau said.
To make a recovery, HTC will have to go a lot deeper than simply moving around executives, she added.
Earlier this month, HTC unveiled an updated version of its HTC One smartphone. It has been criticized for looking too similar to the previous generation, and will have to compete against Samsung's upcoming Galaxy S6 and Galaxy S6 Edge devices, which will arrive next month.
HTC's new CEO said she wanted to apply the company's thinking in smartphones to other connected products and services. She pointed to the new HTC Vive, a virtual reality product, as an example.