The purple dress symbolizes Belly’s youthful self-absorption and her naive belief that she knows exactly what’s going on with her friends and family. The previous summer, Belly was out shopping with Susannah and Mom when she came across the dress, which Susannah encouraged her to try on. Despite the fact that the styling of the dress is, according to Mom, too mature for her 14-year-old daughter, Susannah insisted on buying the dress for Belly herself. Mom, however, refused to let her friend buy the dress. This contributes to the huge rift between Belly and Mom: Belly believes that Mom is wholly unsympathetic and doesn’t care about her. It’s this belief about Mom’s motives and goals that leads Belly to conclude, when she finds the dress tucked into her suitcase upon arriving home, that Susannah must’ve bought her the dress and snuck it into her suitcase. Susannah is the generous one who encourages Belly to explore and celebrate her burgeoning womanhood, so of course Susannah is the only woman who Belly thinks would buy her the dress.
However, in the novel’s present, Belly realizes, with Susannah’s help, that Mom actually bought her the dress and presumably allowed Belly to spend the last year believing Susannah did it. This in and of itself speaks to Mom’s care for Belly and her selflessness: she clearly never expected a thank-you, and she seemed to have no intention of correcting Belly’s assumptions about who bought the dress. As Belly learns this information, she begins to reevaluate her preconceived notions about who Mom is and whether and how Mom cares about her. As Belly comes to a more nuanced and correct understanding of who her mother is, she begins to come of age and develop more empathy and compassion for other people.
The Purple Dress Quotes in The Summer I Turned Pretty
“I’ll wear that dress you bought me last summer.”
“What dress?”
“The one from that mall, the purple one that you and Mom fought over that time. Remember, you put it in my suitcase?”
She frowned, confused. “I didn’t buy you that dress. Laurel would’ve had a fit.” Then her face cleared, and she smiled. “Your mother must have gone back and bought it for you.”
“My mother?” My mother would never.
“That’s your mother. So like her.”
“But she never said…” My voice trailed off. I hadn’t even considered the possibility that it had been my mother who’d bought it for me.
“She wouldn’t. She’s not like that.” Susannah reached across the table and grabbed my hand. “You’re the luckiest girl in the world to have her for a mother. Know that.”

