She will replace Pablo Isla, who has been chairman since 2011, in April, the company said in a statement. He was deputy chairman between 2005 and 2011.
Ortega, 37, has been working for the company in different areas for the last 15 years, even working anonymously as a shop employee at one point to learn the ins and outs of the company.
She is the youngest daughter of Amancio Ortega, 85, who founded fast-fashion giant Zara with his ex-wife Rosalia in 1975 in Spain’s northwestern region of Galicia.
He remains the firm’s largest shareholder with a 59 percent stake and is one of the world’s richest men.
“I have lived and breathed this company since my childhood, and I have learned from all the great professionals I have worked with over the last 15 years,” Marta Ortega said in the statement.
“I have always said that I would dedicate my life to building upon my parents’ legacy, looking to the future but learning from the past,” she added.
Inditex, which operates nearly 7,000 stores worldwide, posted a net profit of almost 1.3 billion euros ($1.5 billion) during its first half of 2021, which runs between February and July.
The fashion group owns seven other brands in addition to Zara, including upmarket Massimo Dutti and teen label Stradivarius.
It is the world’s biggest fashion retailer, ahead of Swedish rival H&M.
Inditex thanked Isla, who is resigning, for his “leadership and vision” during his 17 years at the firm, saying the group had become “the leading company in its sector worldwide” under his watch.
It also hailed Marta Ortega, saying she “has led the strengthening of Zara’s brand image and fashion proposition, an area she will continue to oversee.”
She studied international business in London and carried out months-long stays in the departments of finance, accounting, sales analysis and design when she began working at Inditex.
Marta Ortega also briefly worked as an anonymous employee at the group’s shops in 2007, reportedly stocking shelves, to get a better understanding of how they operate.
Oscar Garcia Maceiras, who had become the company’s general counsel and secretary of the board in March, will become CEO “effective immediately”, Inditex said.
Her will replace Carlos Crespo, who took the post two years ago. Crespo will remain chief operating officer.