Gwen Tennyson (Classic)/Family

Natalie and Frank Tennyson
Despite Gwen's parents disapproving her life style, especially Natalie, they never tried to stop her, they love their daughter and they are supportive her decisions no matter what which is seen in What Are Little Girls Made Of?.

Sunny
Gwen loved playing with Sunny when they were younger. In Girl Trouble, Gwen showed to be extremely irritated by Sunny's behavior (e.g. flirting with Kevin), while Sunny developed a grudge against Gwen's due to everyone telling her to be like her cousin, when the two fought Sunny overpower Gwen until Verdona came to take Sunny, before Verdona leaving Gwen tells her not to be hard on Sunny because despite being a pain, she is still family.

Verdona
When Gwen first met Verdona, they both started off on the wrong foot, battling each other. Shocked to see her manipulate mana, Verdona was soon revealed to be Gwen's grandmother. Verdona explained that Gwen had the "spark" ever since she saw her use her powers and revealed much of her alien powers and background. Verdona then tried to influence Gwen into training with her on her home planet, Anodyne, which would take about seventy-five years to master. Refusing the offer, Gwen decided to stay home. Angered, Verdona tried to force the inner Anodite out of Gwen by fighting her. Fed up, Gwen demanded her to stop and eventually came to understanding terms with her. Verdona flew home and promised to revisit every now and again.

Lucy Mann
When they were kids, Lucy loves teasing and tricking Gwen a lot. Some examples like teasing Gwen that she likes Kevin when she was younger. In Mud Is Thicker Than Water, Gwen was shocked to see Lucy who became a Plumber in a short amount of time. Lucy also disguised herself as Kevin, making Gwen confused since he went to the auto show with Rook. Lucy tricked Gwen making her angry again. Throughout this episode, due to Gwen always being tricked and teased by Lucy, Gwen suspected Lucy to be the spy in the Plumbers Headquarters stealing Plumber Tech. In the end, Grandpa Max revealed that Lucy was actually posing as Liam to find out the real traitor, leaving Gwen feeling sorry for herself and Lucy. In the end, the two of them started talking.

From Hedorium to Eternity, 11 year old Lucy disguised herself as Kevin and tricked Gwen. Due to Gwen blushing, she gets the fact that Gwen likes Kevin, leaving her irritated and started chasing each other. In this episode, they did work together into kicking Ben's soccer ball and scoring a goal, leading their teamwork to a success.