We herein present a case of a 71‐year‐old woman with primary Sjogren's syndrome (SjS), who developed bilateral pleural effusion and ground glass opacity during treatment with low‐dose prednisolone. The pleural effusion and bronchoalveolar lavage fluid revealed elevation of lymphocytes. Thoracoscopic pleural biopsy showed infiltration of lymphocytes with no evidence of other diseases, confirming SjS‐related pleuritis. Therefore, we initiated 20 mg prednisolone and pleural effusion was rapidly resolved. Our results indicate that SjS can be rarely complicated with pleuritis. In addition, thoracoscopic pleural biopsy and a rapid response to steroid treatment would be helpful for diagnosing SjS‐related pleuritis.