Abstract The aim of this work was to investigate how the heat-induced gelation of micellar casein (MC)-plant protein mixtures in aqueous solution is affected by protein composition (MC/plant proteins = 100/0 to 0/100) and total protein content (4%, 6% and 8% w/w) at pH 5.8 and 6.0. Two types of plant proteins were used: soy proteins (SP) and pea proteins (PP). Storage moduli (G′) were measured during heating ramps from 20 to 90 °C and heat-induced gelation was characterised by a sharp increase in G′ at a critical temperature (T c). The gel stiffness (G el) was determined after 1 h at 90 °C and the microstructure before and after heating was investigated by confocal laser scanning microscopy (CLSM). T c was found to increase with increasing the fraction of MC replaced by SP or PP, due to binding of calcium to the plant proteins. The effect was stronger for SP, which bound calcium more efficiently than PP. T c decreased with decreasing pH, possibly caused by decreased electrostatic repulsion and increased calcium release from MC. G el increased with increasing total protein content and did not depend significantly on the pH. Interestingly, G el showed a minimum as a function of the plant protein fraction (40% for SP and 70% for PP) in the mixtures. It is concluded that MC and plant proteins did not co-aggregate in the mixtures during heating, and that each type of protein formed networks independently. Graphical abstract Unlabelled Image Highlights • Micellar casein (MC)-plant protein (PLP) mixtures gel during heating at low pH. • Gel stiffness shows a minimum as a function of the PLP fraction in the mixtures. • MC and PLP do not co-aggregate in the mixtures during heating. • Network formation of MC and PLP upon heating is independent in the mixtures. • MC can be partially replaced by PLP to create innovative food products. [ABSTRACT FROM AUTHOR]