OBJECTIVE: This study aimed to assess the causality of allergic diseases and celiac disease. METHODS: We collected summary-level data from publicly available genome-wide association studies to conduct our bidirectional two-sample and multivariable Mendelian randomization analysis. Furthermore, a series of sensitivity analyses were applied to validate our findings. RESULTS: In bidirectional two-sample MR analyses, we found a significant causal effect of atopic dermatitis (AD) on CD (Inverse-variance weighted (IVW): odds ratio [OR] = 1.302, 95% confidence interval [CI] = 1.152-1.471, CONCLUSIONS: Our study suggests that AD is a risk factor for CD and it is considered suggestive of a causal relationship between asthma and CD. Further research is needed to explore the potential mechanisms underlying this causal effect.