Background: Evidence on how decisions regarding escalation to triple therapy and de- or re-escalation are taken and the rationale on which these decisions are based is currently limited in Germany. Objectives: The TETRIS study aims to elucidate influences on treatment decisions surrounding triple therapy in a real-world practice setting in Germany. Design: TETRIS is an ongoing, multicenter, prospective, observational cohort study recruiting patients with chronic obstructive pulmonary disease (COPD) with or without asthma who have already been treated with triple therapy for 2–48 weeks. Methods: For better representation of the treatment reality in Germany, patients are recruited from general practitioners and pulmonologists. Data are collected in two parts. Part 1 involves cross-sectional phenotyping of patients at enrollment. Part 2 involves a 2-year longitudinal follow-up period to monitor/document all visits by the patients during the 24-month observation period per routine clinical practice. Here, we report the demographic and baseline characteristics of 1213 eligible patients recruited to part 1 of the study. Results: The mean patient age was 66.4 years overall, and 29.3% (356/1213) of patients had no comorbidities. The mean CAT score was 19.4; the number of exacerbations and hospitalizations due to exacerbations in the past 3 years before starting triple therapy was 0.6 and 0.1, respectively. Dual bronchodilation with a long-acting muscarinic antagonist (LAMA) plus a long-acting β-2 agonist (LABA) was the most common therapy for COPD before initiation of triple therapy in 58.3% of patients. Conclusion: In this real-world setting in Germany, patients with COPD have a relatively low reported exacerbation rate but high symptom burden, and over 70% are multimorbid. Triple therapy is initiated in patients who are primarily highly symptomatic despite being on LAMA + LABA. Future prospective studies in patients with multimorbidity are warranted to better understand the treatment landscape across the disease spectrum. Trial registration: https://clinicaltrials.gov/study/NCT04657211