Background: Interleukin (IL)-33 produces interferon-γ (IFN-γ) which plays a crucial role in Mycobacterium tuberculosis induced pleural responses. We aimed to identify the association between pleural IL-33 levels and tuberculous pleurisy and their diagnostic value. Methods: Pleural IL-33, ST2 (a receptor of IL-33), adenosine deaminase (ADA), and IFN-γ, as well as serum IL-33 and ST2 were measured in 220 patients with pleural effusions (PEs; malignant [MPEs], parapneumonic [PPEs], tuberculous [TPEs], and cardiogenic [CPEs]). Results: Pleural and serum IL-33 levels were highest or tended to be higher in TPEs than in other PEs. The median pleural fluid-to-serum IL-33 ratio was higher in TPE cases (≥0.91) than in other PE cases (≤0.56). Pleural IL-33 correlated with pleural ADA and IFN-γ. However, the diagnostic accuracies of pleural IL-33 (0.74) and pleural fluid-to-serum IL-33 ratio (0.75) were lower than that of ADA (0.95) or IFN-γ (0.97). Pleural ST2 levels in MPEs were higher than in TPEs. SerumST2 levels did not differ between the groups. Conclusions: We identified an association between elevated pleural IL-33 levels and tuberculous pleurisy. However, we recommend conventional pleural markers (ADA or IFN-γ) as diagnostic markers of TPE.