Achalasia is an esophageal motility disorder associated with abnormalities in peristalsis and lower esophageal sphincter (LES) relaxation. The etiology of the disease remains elusive. It is often misdiagnosed initially as gastroesophageal reflux disease. Patients with achalasia often complain of dysphagia to solids and liquids but may focus on regurgitation as the primary symptom, leading to the early misdiagnosis. Chest pain, weight loss, and occasional vomiting may be additional symptoms encountered in those with achalasia. The disease may be suspected on the basis of clinical presentation, but diagnosis depends on classic findings using high‐resolution manometry, showing either failed or simultaneous contractions with associated normal or high LES pressures with no or incomplete relaxation with swallows. There are no cures for achalasia, and, in most patients, treatments have to be repeated over time. Definitive treatment options in achalasia include pneumatic dilation, surgical myotomy, and the new technique of per‐oral endoscopic myotomy. Botulinum toxin (Botox) or other medical therapies are often reserved for those who cannot have definitive therapies owing to comorbid conditions.