A lot of effort has been made in developing vaccine and therapeutic agents against the SARS-CoV-2, concentrating on the Spike protein that binds angiotensin-converting enzyme 2 on human cells. Nowadays, some researches study the role of the N -linked glycans as potential targets for vaccines and new agents. Due to the flexibility and diversity of the N -linked glycans, in this work, we focus on the N -Acetylglucosamine moiety, which is the precursor of nearly all eukaryotic glycans. We performed molecular dynamics simulations to study the effects of the N -Acetylglucosamine on the stability of the spike glycoprotein in SARS-CoV-2. After a 100 ns of simulation on the spike proteins without and with the N -Acetylglucosamine molecules, we found that the presence of N -Acetylglucosamine increases the local stability in their vicinity; even though their effect on the full structure is negligible. Thus; it can be inferred that the N -Acetylglucosamine moieties can potentially affect the interaction of the S protein with the ACE2 receptor. We also found that the S1 domain is more flexible than the S2 domain. We propose which of the experimentally observed glycans found on the spike may be more functional than the others. Detailed understanding of glycans is key for the development of new therapeutic strategies.