Reducing the fat content in emulsions can give additional nutritional health benefits. Hence, developing low-fat oil-in-water emulsions, fortified with healthy microalgae providing advantageous properties, is an interesting topic. In this study, the addition of Arthrospira platensis (Spirulina), Chlorella vulgaris (Chlorella), and Dunaliella salina (Dunaliella) microalgae biomass on the physicochemical properties of low-fat oil-in-water emulsion formulations were evaluated. The rheological properties of food emulsions were measured in terms of the viscoelastic, flow behaviour, and textural properties, with all properties studied during 60 days. pH values of all the emulsions ranged between 3.0 and 3.7 and agreed to the Codex Alimentarius Commission. Moreover, their rheological behaviour may be classified as weak gel-like, a distinguishing characteristic of low-fat emulsion products. Substantial differences in rheological properties were observed between the fortified microalgae emulsions over the storage time (60 days). However, incorporating Spirulina or Dunaliella gave emulsions with stable texture, viscoelastic, and rheological properties. The prepared emulsions displayed good colour stability for Chlorella and Dunaliella. Overall, the fortified microalgae low-fat emulsions are expected to provide a blueprint for the design of low-fat mayonnaise-like food emulsions.