<p>Heart failure (HF) is a chronic and progressive condition associated with significant morbidity and mortality and reduced quality of life. Among the various comorbidities that exacerbate HF outcomes, iron deficiency (ID) is increasingly recognized as a modifiable risk factor that contributes to decreased exercise capacity, fatigue, and hospitalizations, even in the absence of anemia. Approximately 30–50% of patients with HF present with ID, highlighting the need for routine screening and targeted management. The objective of this review was to summarize the pathophysiological basis, diagnostic criteria, and clinical implications of ID in HF and to provide evidence-based recommendations for its treatment based on current guidelines and clinical trials. Key clinical trials such as FAIR-HF, CONFIRM-HF, and AFFIRM-AHF have demonstrated that intravenous iron supplementation, particularly with ferric carboxymaltose, improves functional status, symptoms, and quality of life in patients with HF and ID. These benefits are observed irrespective of the presence of anemia, and treatment is associated with a favorable safety profile. Current guidelines recommend routine screening for ID in patients with chronic HF and consideration of intravenous iron supplementation in symptomatic patients with confirmed deficiency. Oral iron has shown limited efficacy in this population. In conclusion, ID is a treatable and impactful comorbidity in HF. Early detection and appropriate intravenous iron therapy can significantly improve patient-centered outcomes and should be incorporated into standard HF management strategies.</p>