Sandra Tennyson

Sandra Tennyson is Carl Tennyson's wife, Ben's mother and Gwen's aunt.

Personality
Sandra seems to contradict Carl when it comes to disciplining Ben, being more stern, though, like Carl, she insisted on being addressed by name.

Sandra seems to have a liking for health and fitness as she has been seen exercising with a fitness ball and also has rejected offers of cotton candy, stating that "processed sugar is poison". Ben tries especially hard to avoid eating her "healthy" cooking.

Alien Force
Sandra made a cameo in the first episode, when she was washing dishes and yelling at Ben for running in the house. However, she was a brunette at the time.

In Grounded, Sandra and Carl witnessed Ben and Gwen fighting a Highbreed. She and Carl became angry at Ben for lying to them so many times and forbid Ben from using the Omnitrix. However, Ben disobeys them when Kevin is in trouble. Sandra and Carl spot Echo Echo trying to sneak out of the house and then he is grounded. Ben later blatantly disobeys them and transforms into Humungousaur right in front of them to leave and help Kevin, and Sandra and Carl realize Ben is trying to protect Earth, and they realize they were wrong to stop him, they then decide to go help Ben save Kevin. Carl and Sandra save Humungousaur and Kevin from the Highbreed using a Space Bazooka. She and Carl apologized for the mistake they made and promised to never let that happen again.

Ultimate Alien
Sandra returned in Hit 'Em Where They Live, where she, along with Ben's family, are attacked by Ben's enemies. When she was washing dishes, she was ambushed by Sevenseven without even realizing it, but was saved by Max. Later in the episode, she was kidnapped by Zombozo and taken to an abandoned carnival. She was saved by Gwen.

Omniverse
Sandra reappeared in Rules of Engagement, where Princess Looma meets her.

She later appeared in O Mother, Where Art Thou?, and convinced Ma Vreedle not to destroy Earth. She also cooked healthy food to Ben and Rook, following them around for most of the episode with Ben's leftovers.

In Vreedlemania, she brought Ben and Rook along to a dinner with Ma Vreedle and her family, having become friends with the criminal matriarch. When the reunited Vreedles cause trouble in Bellwood, Sandra manages to talk Ma Vreedle into stopping, and later comforts her when Pa Vreedle runs out on her.

In The Most Dangerous Game Show, Sandra briefly appears as one of the contestants chosen by Charles Zenith to compete for Ben's hand in marriage, but is removed from the game when Ben points out their relation.

Ben 10

 * Ben 10: Destroy All Aliens (first chronological appearance)

Ben 10: Alien Force

 * Ben 10 Returns: Part 1 (first appearance; cameo)
 * Grounded

Ben 10: Ultimate Alien

 * Hit 'Em Where They Live (first re-appearance)
 * The Ultimate Enemy: Part 2 (flashback; cameo)

Ben 10: Omniverse

 * Rules of Engagement (first re-appearance)
 * O Mother, Where Art Thou?
 * Vreedlemania
 * The Most Dangerous Game Show (cameo)

Cartoon Network Action Packs

 * Double Trouble
 * Lazy Day

Trivia

 * According to Derrick J. Wyatt, she and Carl approve of Ben's friendship with Rook.
 * In Ben 10 Returns: Part 1, Sandra was a brunette, instead of a blonde, like she was before and after that episode, making it unclear which one is her natural hair color.
 * Sandra's name is pronounced differently in the movie than the series.
 * Sandra does not appear to be fond of Kevin much; calling him Ben's "ruffian friend".
 * Despite this, Sandra approves of Ben and Kevin's friendship.
 * Sandra did not know about Ben's engagement to Looma until Rules of Engagement.