The Vietnamese-American actress, who played Rose Tico in The Last Jedi, was subjected to abusive comments and harassment from some fans who took aim at her ethnicity and appearance.
Tran, 29, deleted all her Instagram posts and left a line in her biography that reads, "afraid, but doing it anyway".
In response, The Last Jedi director Rian Johnson hit out at the trolls and described them as "manbabies".
"On social media a few unhealthy people can cast a big shadow on the wall, but over the past 4 years I've met lots of real fellow SW fans," Johnson said. "We like & dislike stuff but we do it with humour, love & respect. We're the VAST majority, we're having fun & doing just fine."
Tran's withdrawal from social media followed in the footsteps of co-star Daisy Ridley, who quit Instagram last year saying it was "highly unhealthy for people's mental health".
"I don't do social any more. I came off it last September and I will never get back on," the 26-year-old told Radio Times. "It's such a weird thing for young people to look at distorted images of things they should be."
The next Star Wars movie, Episode IX, is set to be released in December 2019.