The final step in the protein biogenesis pathway is the acquisition of the native, biologically active conformation. Failures in this complex process or in the maintenance of the native conformation can trigger the formation of toxic protein aggregates, which are the underlying cause of some of the most devastating human diseases, such as Parkinson’s disease, Alzheimer’s disease, and Creutzfeldt-Jakob disease. Our research focuses on the molecular mechanisms that ensure the efficiency of this process in the secretory pathway of eukaryotic cells. Approximately one-third of the eukaryotic proteome belongs to the secretory pathway. These proteins enter the endoplasmic reticulum (ER) or are inserted into its membrane during their synthesis. In the ER, several molecular chaperones and folding-facilitating enzymes assist in the folding process of thousands of different proteins. In addition, most of these proteins undergo post-translational chemical modifications, with the addition of N-glycans being the most common and drastic. Frequently, this modification is necessary to acquire a correct fold and/or to properly target these proteins to their final destination. Our aim is to understand how these intricate proteostasis systems coordinate their activities to ensure the efficiency of the folding process in the cells. To this end, we employ diverse molecular, cellular, biophysical, and bioinformatics approaches, combining experiments performed in vivo, in vitro, and in silico.