Imran Khan, Snap’s chief strategy officer and one of the few executives remaining at the struggling company since its 2017 public offering, is stepping down.

On Monday, the company said in a regulatory filing that Mr. Khan would remain at the company until his replacement was hired. Afterward, he is expected to set up a firm that will both help and invest in technology start-ups, according to a person with knowledge of the matter.

“There is never a perfect time to say goodbye,” Mr. Khan said in the filing, “but we have a stellar leadership team in place to guide Snap through the next chapter, and I plan to stay on to ensure a very smooth transition.”

He is the latest top executive to leave Snap at a turbulent time for the once high-flying social network, which is run by Evan Spiegel. The company’s former head of engineering, Tim Sehn, left in December; its head of product, Tom Conrad, was replaced in March; and Snap brought in a new chief financial officer, Tim Stone, in May.