Background: Allergic rhinitis (AR), asthma, chronic obstructive pulmonary disease (COPD), and rhinosinusitis are common and little studied in the Asia-Pacific region. Objectives: We sought to investigate real-world practice patterns for these respiratory diseases in India, Korea, Malaysia, Singapore, Taiwan, and Thailand. Methods: This cross-sectional observational study enrolled adults (age ≥18 years) presenting to general practitioners (GP) or specialists for physician-diagnosed AR, asthma, COPD, or rhinosinusitis. Physicians and patients completed study-specific surveys at one visit, recording patient characteristics, health-related quality of life (QoL), work impairment, and healthcare resource use. Findings by country and physician category (GP or specialist) were summarized. Results: Of the 13,902 patients screened, 7,243 (52%) presented with AR (18%), asthma (18%), COPD (7%), or rhinosinusitis (9%); 5,250 of the 7,243 (72%) patients were eligible for this study. Most eligible patients (70–100%) in India, Korea, Malaysia, and Singapore attended GP, while most (83–85%) in Taiwan and Thailand attended specialists. From 42% (rhinosinusitis) to 67% (AR) of new diagnoses were made by GP. On average, patients with COPD reported the worst health-related QoL, particularly to GP. Median losses of work productivity for each condition and activity impairment, except for asthma, were numerically greater for patients presenting to GP vs. specialists. GP prescribed more antibiotics for AR and asthma, and fewer intranasal corticosteroids for AR, than specialists (p < 0.001 for all comparisons). Conclusions: Our findings, albeit mostly descriptive and influenced by between-country differences, suggest that practice patterns differ between physician types, and the disease burden may be substantial for patients presenting in general practice.