N-linked glycosylation is a posttranslational modification that has significantly contributed to the rapid evolution of HIV-1. In particular, enrichment of N-linked glycosylation sites can be found within Envelope variable loops, regions that play an essential role in HIV pathogenesis and immunogenicity. The web server described here, the HIV N-linked Glycosylation Site Analyzer, was developed to facilitate study of HIV diversity by tracking gp120 N-linked glycosylation sites. This server provides an automated platform for mapping and comparing variable loop N-linked glycosylation sites across populations of HIV-1 sequences. Furthermore, this server allows for refinement of HIV-1 sequence alignment by using N-linked glycosylation sites in variable loops as alignment anchors. Availability of this web server solves one of the difficult problems in HIV gp120 alignment and analysis imposed by the extraordinary HIV-1 diversity. The HIV N-linked Glycosylation Site Analyzer web server is available athttp://hivtools.publichealth.uga.edu/N-Glyco/.