Complex medical therapies such as outpatient parenteral antimicrobial therapy (OPAT), typically performed in acute care hospital, are moving to the home setting, requiring patients and informal caregivers to perform complicated medical tasks. This study sought to describe patient, caregiver, and health care worker’s understanding of their roles in OPAT and barriers to fulfilling these roles. Role ambiguity was a consistent finding in all three groups highlighting the need for enhanced training for people performing these tasks.