Patients with resolved hepatitis B virus (HBV) infection who are treated for hematological malignancies remain at risk for HBV reactivation. Because of conflicting studies about whether the antibody to hepatitis B surface antigen (anti‐HBs) protects against reactivation in patients with resolved infection (hepatitis B surface antigen negative) receiving chemotherapy for hematological malignancies, we conducted a meta‐analysis to determine if anti‐HBs reduces HBV reactivation risk. We sought English‐language studies through March 1, 2016, in Medline and other sources that examined reactivation in patients with resolved HBV infection receiving chemotherapy for hematologic malignancies. The absolute risks and odds ratio (OR) of reactivation with versus without anti‐HBs were estimated in random‐effects model meta‐analyses. In 20 studies involving 1,672 patients not receiving antiviral prophylaxis, the reactivation risk was 14% (95% confidence interval [CI] 9.4%‐19%) in 388 patients who had antibodies to hepatitis B core antigen only versus 5.0% (95% CI 3.0%‐7.0%) in 1,284 patients who also had anti‐HBs. Anti‐HBs reduced reactivation risk with a pooled OR of 0.21 (95% CI 0.14‐0.32) versus patients with antibody to hepatitis B core antigen only. Similar results were found when limiting the analysis to rituximab chemotherapy (OR = 0.19, 95% CI 0.11‐0.32) and lymphoma (OR = 0.18, 95% CI 0.11‐0.28). Conclusion: In patients with resolved HBV receiving chemotherapy for hematological malignancies without antiviral prophylaxis, anti‐HBs positivity is associated with a decreased risk of reactivation; HBV screening in this patient population should include the routine use of anti‐HBs, and those who are anti‐HBs‐negative should receive antiviral prophylaxis. Future studies should examine the effect of anti‐HBs serum titers, the potential role for booster vaccinations, and antiviral prophylaxis prior to chemotherapy in this patient population. (Hepatology 2017;66:379–388).