Although many studies have shown that hyperbaric oxygen (HBO) therapy can significantly improve symptoms and quality of life of patients affected by femoral head necrosis, this therapy is not worldwide approved yet. This meta-analysis was performed to evaluate its clinical effect. Relevant studies published before May 2020 were systematically searched using terms related to HBO and femoral head necrosis. Fixed and random-effects models were used to estimate the odds ratio (OR) with 95% confidence intervals (CI). Subgroup analyses and publication bias tests were carried out to explore potential study heterogeneity and bias. Ten studies involving 353 controls and 368 HBO-treated cases were included, most of which were conducted on Asian population. The clinical effect in the HBO therapy group was 3.84 times higher than in the control group (OR = 3.84, 95% CI (2.10, 7.02), p < 0.00001). Subgroup analyses showed that the clinical effect of HBO therapy was statistically significant in the Asian subpopulation which represented most of the subjects (OR = 3.53, 95% CI (1.87, 6.64), p < 0.00001), but not in the non-Asian subpopulation, probably because of insufficient numerosity (OR = 7.41, 95% CI (0.73, 75.71), p = 0.09). The results of this meta-analysis suggest that patients with femoral head necrosis treated with HBO therapy can achieve a significant clinical improvement.