A comprehensive understanding of gastrointestinal anatomy is essential for performance of any endoscopic procedure. Surgical approaches to therapy have become increasingly common in the past decade, which has resulted in a substantial proportion of patients with surgically altered anatomy who require endoscopy. In parallel with the obesity epidemic, bariatric surgery for obesity management has been widely adopted. In response to these trends, gastroenterologists must become familiar with patient anatomy after these surgical interventions and understand the implications of this altered anatomy on the current array of available endoscopic modalities for diagnosis and therapy. This review describes the range of surgically altered anatomy commonly encountered in the upper gastrointestinal tract. For each foregut location—esophagus, stomach, and small bowel—we describe indications for and specific details of the range of common surgical approaches affecting this regional anatomy. We then provide an endoscopic roadmap through the altered anatomy resulting from these surgical interventions. Finally, we address the impact of postsurgical anatomy on performance of endoscopic ultrasound and endoscopic retrograde cholangiopancreatography, with guidance surrounding how to successfully execute these procedures. Evolution of endoscopic approaches over time might be expected to enhance the safety and efficacy of these interventions in patients with surgically altered anatomy.