Marie Nixon, from Sunderland, tweeted out a photo of the top for girls aged three to 16 years old, with her own edit, changing “with” to “I’m in”.
@nextofficial, I’ve fixed this little girl’s T-shirt for you,” she wrote on 12 December.
The photo was retweeted nearly 200 times and liked more than 330 times in two days. Others also expressed their disappointment at the T-shirt’s slogan.
Replying to other tweets, Nixon, said she was “furious” and said she believes the top should be withdrawn from shops ASAP.
Next replied to Nixon saying they had passed on feedback to the relevant team.
The T-shirt was still available on Next’s website for girls aged three to 16 at the time of writing.
A spokesperson for Next told The Huffington Post UK: “It certainly wasn’t our intention to produce something that might be perceived as sexist, so we apologise for any offence caused.”