In the tragic story of Hamlet, there are many victims. Some are victims of their own poor choices and others of circumstances beyond their control. Ophelia is most certainly a victim due to forces beyond her control.
Ophelia appears to be a good, honest, and sincere person, one of the few such characters in this play. She dutifully consents to her father's command to stop seeing Hamlet. She even allows Polonius to use her as bait in order to gather information on Hamlet. Throughout the story, Ophelia is obedient to the will of men who, with the possible exception of Laertes, see her as a means to an end—someone useful. No one shows any real concern for Ophelia's feelings and well-being. Even Laertes seems disinterested in what could really be driving his sister mad.
When Hamlet verbally abuses Ophelia in act 3, scene 1, Ophelia is helpless to defend herself. Ophelia also receives derisive insults and disparaging innuendo from nearly everyone else, including Laertes, Polonius, and Claudius. She has been brought up to be timid and meek. As a result, she internalizes this abuse without fighting back. She has no confidants or anyone truly on her side.
This isolation and abuse lead Ophelia into madness and eventually to her suicide. Yet, even this is presented as passive. According to Gertrude, Ophelia did not so much kill herself as prevent herself from drowning. As a powerless victim of circumstances, we can confidently call Ophelia a victim.