The purpose of this study was to compare the management of patients with a history of penicillin allergy between allergists and non-allergists in Thailand. A questionnaire was distributed to Thai physicians by online survey. The answers from 205 physicians were analyzed. The discrepancy of penicillin allergy management between allergists and non-allergists was clearly demonstrated in patients with a history of an immediate reaction in the presence of penicillin skin test (P < 0.01) and in patients with a history of Stevens-Johnson syndrome (P < 0.05) from penicillin. Allergists are more willing to confirm penicillin allergic status, more likely to carefully administer penicillin even after negative skin test, but less concerned for the potential cross-reactivity with 3rd and 4th generation cephalosporins, compared to non-allergists. The lack of penicillin skin test reagents, the reliability of penicillin allergy history, and medicolegal problem were the main reasons for prescribing alternate antibiotics without confirmation of penicillin allergic status. In summary, the different management of penicillin allergy between allergists and non-allergists was significantly demonstrated in patients with a history of severe non-immediate reaction and in patients with a history of an immediate reaction when a penicillin skin test is available.