The manager of a Nashua, N.H.-based T.J. Maxx ordered a service dog with its owner to leave the store or be put in a carriage.
Sydney, along with her mother Celeste, was injured during the April 2013 bombing.
Celeste lost both her legs in the attack, while Sydney suffered shrapnel wounds.
Celeste and Sydney have become inspirations, over the course of their ongoing recovery since the attack.
As a result of the attack, Sydney is now battling post-traumatic stress disorder and said her service dog, Koda, has been crucial to her recovery.
Even though Koda was clearly identified as a service dog, the T.J. Maxx store manager said to Sydney, "If you want to keep your dog in the store, you have to put him in the carriage."
According to the Americans with Disabilities Act of 1990, all businesses must allow service animals in public areas.
It is only legal to ask the owner if the dog is, indeed, a service dog, and what tasks it performs.