Heart failure with preserved ejection fraction (HFpEF) remains a complex and therapeutically challenging syndrome. A subset of HFpEF patients with left bundle branch block (LBBB), wide QRS complexes (≥130 ms), and mechanical dyssynchrony may benefit from cardiac resynchronization therapy (CRT). While CRT is an established therapy in heart failure with reduced ejection fraction (HFrEF), its role in HFpEF is under active investigation. Emerging data from mechanistic studies, case reports, and observational trials suggest CRT may offer promising hemodynamic signals, functional improvement, and quality of life enhancement in carefully selected HFpEF patients. This review critically examines the pathophysiological rationale, evolving evidence base, patient selection criteria, and future directions for CRT in HFpEF with LBBB.