Background Medication use typically involves physicians prescribing, pharmacists reviewing, and nurses administering medications to patients. Drug information (DI) is often required during the process, with the various health care professionals (HCPs) seeking information differently according to their needs and familiarity with various resources. Objective This systematic literature review aims to evaluate studies on drug information‐seeking behaviour (ISB) of physicians, nurses and pharmacists to ascertain their DI needs, DI sources used, facilitators and barriers to DI‐seeking. Methods A systematic search was conducted on PubMed, http://embase.com, Scopus, PsycINFO, CINAHL and Cochrane Library to identify eligible primary research articles published between January 2000 and May 2020. Results The reviewed studies (N = 48) revealed that HCPs have a wide range of DI needs, with the top needs being similar across the three HCPs. Information sources used most often by all three groups were tertiary, followed by human and primary sources. Factors relating to the source characteristics were the most reported facilitators and barriers to DI‐seeking. Some differences in drug ISB were also identified. Conclusion Our findings can also guide information providers and educators to optimize information provision. It may also facilitate effective communication amongst HCPs when obtaining DI from or providing DI to one another.