Essential oils from certain condiments can be used as promising natural additives in some food products. Their application in liquid form can have some disadvantages, mainly volatilization and hydrophobicity, being encapsulation an alternative for reducing these drawbacks. This study aimed to evaluate the influence of polymers and the cationic bath concentration on marjoram essential oil (MEO) microencapsulation by ionic gelation. Process variables, such as concentration of sodium alginate (0.5 to 2 g/100g), whey protein isolate (WPI) (0.5 to 2 g/100g), and CaCl2 bath (50 to 300 mM), were used as factors in a 23 rotatable central composite design to evaluate the influence of these parameters on the encapsulation efficiency (EE), emulsion droplet size, and bead circularity. Emulsions were prepared with sodium alginate, WPI, and MEO (2g/100g) in Ultra-Turrax (16000 rpm/5 min). For bead production, emulsions were dripped and the beads remained under magnetic stirring for 30 minutes in the CaCl2 bath. EE was determined by hydrodistillation, the emulsion droplet size by laser diffraction, and bead circularity by a digital image processor. EE ranged from 45.6 to 66%, inversely proportional to alginate concentration. D[3,2] of the emulsions ranged from 1.10 to 1.73 µm. The increase in alginate and WPI concentration led to a decrease in droplets size, due to the high emulsion viscosity and lower surface tension. Considering that the beads obtained by ionic gelation are generally porous, smaller emulsion droplets may have easily diffused through the pores, reducing EE. Lower alginate and WPI concentrations resulted in higher EE and lower circularity. Thus, an intermediate concentration of sodium alginate (1.25 g/100g), WPI (1.25 g/100g), and CaCl2 (175 mM) were selected as the most appropriate conditions to produce beads with satisfactory circularity and good EE. MEO was successfully encapsulated by ionic gelation showing beads with promising physical-chemical composition for food applications.