Amanda Duff (voiced by Soleil Moon Frye) appears to be the typical teenage girl and is the oldest child or MacArthur and Emily Duff she is also the older sister of both Elmyra, Duncan and an infant sibling.
Amanda is bratty, ungrateful, sassy, and mean towards some members of the family. Amanda seems to more interested in her social life at school or anywhere outside of the house because it has be indicated that she rather talk to her friend Stephanie than help her family member. In Take Elmyra, Please she seem to have a problem to help her mother to catch her little brother who got out of his crib and was causing a mini rampage throw the living room.
In addition she has told Duncan to get a life and talks harshly to both Duncan and Elmyra but, in Grandma's Dead she has shown a small act of kindness towards Elmyra knowing the fact that one of her hamsters died due to old age.
Amanda is the only one in the family that is neither a redhead nor a brunette but, she appears similar to her father MacArthur in appearance but, it could be that she dyes her hair purple for that punk rock look she has. Another indication that she enjoys punk rock that in Take Elmyra, Please she was listening to rock music while talking on the phone to her friend Stephanie.
- "*Grunt.* Unbelievable!!!!"
- "Mickey Butler called me cute."
- "Get a life!"
- "Somebody pinch me."
- "No, they're coming here to give you your own show, elbow-head."