Immersive virtual reality (IVR) has demonstrated significant potential in educational contexts. Nonetheless, prior IVR implementations have primarily focused on visual and auditory simulations, neglecting olfaction, which has limited immersive learning. To address this gap, we conducted an experimental study involving 64 students to examine the impact of integrating olfactory stimulus into IVR systems for fire safety training. Participants were randomly assigned to the control group (without olfactory stimulus, n = 32) or the experimental group (with olfactory stimulus, n = 32). The results indicated that the integration of olfactory stimulus significantly promoted high-arousal positive emotions, increased sense of presence, and reduced cognitive load—although it did not significantly improve learning performance. Thematic analysis further revealed that the incorporation of olfactory stimulus provided learners with an immersive learning experience. Moreover, this IVR system with olfactory stimulus had a high quality of experience. These findings have significant implications for the practice of learning in IVR and multisensory learning theory.