Primary care is increasingly geared toward standardized care and decision-making for common chronic conditions, combinations of medical and mental health conditions, and the behavioral aspects of care for those conditions. Yet even with well-integrated team-based care for health conditions in place, some patients do not engage or respond as well as clinicians would wish or predict. This troubles patients and clinicians alike and is often chalked up informally to "patient complexity." Indeed, every clinician has encountered complex patients and reacted with "Oh my gosh"-but not necessarily with a patterned vocabulary for exactly how the patient is complex and what to do about it. Based on work in the Netherlands, patient complexity is defined here as interference with standard care and decision-making by symptom severity or impairments, diagnostic uncertainty, difficulty engaging care, lack of social safety or participation, disorganization of care, and difficult patient-clinician relationships. A blueprint for patient-centered medical home must address patient complexity by promoting the interplay of usual care for conditions and individualized attention to patient-specific sources of complexity-across whatever diseases and conditions the patient may have.