Background <p>Anemia is a common complication among individuals with a history of gastric cancer, particularly those who have undergone gastrectomy. While previous studies have largely focused on early post-operative periods in hospital-based cohorts, studies on prevalence and associated factors of anemia in long-term, community-dwelling gastric cancer survivors are limited. Thus, this study aimed to estimate the prevalence and association between anemia and anthropometric, functional, and nutritional factors among Korean adults with a history of gastric cancer.</p> Methods <p>This cross-sectional study analyzed data from the Korea National Health and Nutrition Examination Survey (2016–2020). Adults ≥ 30 years who self-reported a physician diagnosis of gastric cancer were included. Anemia was defined as hemoglobin &lt; 13&#xa0;g/dL (males) or &lt; 12&#xa0;g/dL (females). Anthropometric, laboratory, and dietary variables were compared between individuals with and without anemia, and multivariable logistic regression identified factors associated with anemia.</p> Results <p>Among individuals with a history of gastric cancer, the weighted prevalence of anemia was 31.9%. Anemia prevalence was highest among underweight and lowest among obese participants (55.6% vs. 10.5%, <i>p</i> = 0.01). Individuals with anemia had significantly lower body mass index, handgrip strength (HGS), and protein intake than those without anemia. Low HGS (OR = 2.89; 95% CI 1.41–5.92) and insufficient protein intake (OR = 3.26; 95% CI 1.53–6.97) were associated with higher odds of anemia, whereas obesity was independently associated with lower odds of anemia (AOR = 0.17; 95% CI 0.04–0.70).</p> Conclusions <p>Nearly one-third of long-term gastric cancer survivors had anemia, which was linked to low muscle strength and inadequate protein intake. These findings highlight the potential importance of integrating nutrition and functional-health assessments into long-term care to help prevent anemia and improve well-being in this population.</p>