InGaAs-based laser diodes ( LDs) are widely used for decades due to their high resistance to heat, high speeds, high output power and low threshold current. The width of multiple quantum well (MQW) is one of the most essential parameters that is directly linked to the characteristic of LDs. However, tuning the MQW width is a cumbersome task for fabrications. Therefore, this paper examines the effect of multiple quantum well width on the performance of InGaAs/InP-based laser diodes (LDs). The optical and electrical characteristics of laser diodes with varying quantum well widths are numerically analysed using Lumerical software. The results indicate that a 10-nm-wide MQW LD exhibits optimal performance within the 9 to 11 nm range, with a six-period quantum well structure, achieving the lowest threshold current. Additionally, the peak emission frequency is identified and discussed. The simulation results will assist engineers make the most appropriate decision when determining the MQW width for InGaAs-based LDs.