Background and Objectives Nutritional benefits of amaranth addition to maize products have been documented. However, studies of the effect on the final product's rheological and textural properties are scarce. The objective was to study the effect of amaranth addition on masa's rheological properties and the tortilla texture of maize nixtamalized flours obtained by extrusion technology. Findings Composite flours of maize with 0%, 15%, 30%, or 45% amaranth were extruded, and masa and tortillas were obtained. Masa properties were evaluated with dynamic rheology and tortilla firmness with the texture profile analysis. The amaranth addition effect was not linear. Fifteen percent addition increased frequency sweep values for G′ and G″, while 30% and 45% addition decreased them. Tortilla firmness decreased at 2 storage hours for 15% addition compared with maize‐only samples (5440 and 7190 (g‐f)/mm). The effects can be partially explained by differences in starch characteristics. Conclusions Amaranth (15% addition) improved masa viscoelastic behavior and reduced firmness during storage. Besides the nutritional effects, amaranth use at the tested level will be helpful in improving the texture of maize tortillas produced with extruded flour. Significance and Novelty The texture of tortillas obtained by extruded flours has not been reported to be completely satisfactory; therefore, the use of amaranth has the potential to improve the final product quality.