Pulmonary arterial hypertension (PAH) is a progressive disease with a poor prognosis, and its management should be grounded in well-developed clinical practice guidelines (CPG). Thus, we critically assess the methodological quality of the available CPG for pharmacological treatments for PAH. A systematic review (CRD42023387168) was performed in PubMed, Cochrane, Embase, and Tripdatabase (Jan-2023). Eligible records were appraised by four reviewers using the Appraisal of Guidelines, Research, and Evaluation Collaboration tool (AGREE II) and the complementary tool for assessing recommendations' quality and certainty, AGREE REX. Descriptive statistics were used to summarize the data. Overall, 31 guidelines, mainly authored by professional societies (90%), targeting only physicians as primary users (84%), were identified. Guidelines presented a moderate overall quality (scores of 63% and 51% in AGREE II and AGREE REX, respectively), with a few domains showing slight improvements over the years. AGREE II "Scope and Purpose" (94%) and "Presentation Clarity" (99%) domains obtained the highest scores. The items related to "Stakeholder involvement," "Editorial independence," and "Clinical applicability" (AGREE REX) were fairly reported. Conversely, CPG lacks rigor in development (32% score, AGREE II), scarcely discusses the role of stakeholders, and provides deficient data on the implementation of recommendations (scores of 35% and 46% in AGREE II and AGREE REX, respectively). No differences in the quality of guidelines published by different developers or countries were observed (p > 0.05). Methodological weaknesses are common among guidelines addressing PAH treatment, especially regarding scientific rigor, stakeholders' values and preferences, and facilitators and barriers to implementability. Particular attention should be given to developing future guidelines.