Ridd will take up the role in September, based in Snap Inc's London office.
A Snap Inc spokesman said: "We are thrilled to have Tanya join the Snap family."
Ridd has worked at Apple since 2005. According to LinkedIn she was initially head of UK PR, and more recently head of PR for EMEIA. She oversaw corporate PR in areas including tax, environment and supplier responsibility.
She had previously worked at Bite, which held a PR brief with the tech giant for 14 years until 2009.
Snapchat rebranded to Snap Inc in September last year, to position itself as a "camera company". The company ran an IPO earlier this year, with financial comms support from the agency Sard Verbinnen & Co. It went on to raise $3.4bn (£2.7bn).
The company said 'Snapchatters' devote an average of 30 minutes a day to the app, visiting it more than 18 times and sending a total of more than three billion 'Snaps'. It had 1,900 staff at the end of 2016, according to Nasdaq.
Other recent UK hires at Snap Inc include creative strategist Kate Eltringham, formerly of the creative agency Mother, and BBC Three comms chief Colin Watkins in a European comms role.