Fourth-generation networks are expected to integrate heterogeneous wireless technologies. To ensure seamless mobility across disparate wireless technologies, efficient handoff schemes are required to enhance quality of service (QoS) and offer reliable ubiquitous computing environment. This study reviews classical and existing fuzzy approaches adopted for vertical handoff to ensure seamless mobility across overlaid heterogeneous networks. A neuro-fuzzy multi-parameter-based vertical handoff decision algorithm (VHDA) is proposed. The proposed VHDA considers six parameters and applies rule-based system for vertical handoff decision. The number of vertical handoffs measured in a simulated environment shows that average number of vertical handoffs for the proposed VHDA reduces by 13.3 and 29.8% for the existing fuzzy technique and the classical technique, respectively. Further, reduction in number of unnecessary vertical handoffs in the proposed algorithm shows reduction in ping-pong effect by 15.9%, improvement in end-point service availability (ESA) and throughput by 16.57 and 5.97%, with respect to existing fuzzy technique leading towards improved QoS. Finally, the results of performance assessment, carried out using handoff quality indicator (used to quantify QoS) which is dependent upon ping-pong effect, ESA and throughput, show that the proposed VHDA offers better QoS than existing vertical handoff techniques.