In order to dynamically populate values in lightning:combobox using javascript we can create a list variable and push the values. We also require the values like ids associated to the particular option for back-end logic. For example : If we want to show the list of contacts using lightning:combobox component where the option should display the contact name but the value should be the contact id which will be used for back-end logic For this we can create a temporary Map variable in our lightning component and set the value and label parameters of the lightning:combobox. Here is the code for this component Combo.app <aura:application extends="force:slds" access="global" description="Lightning Combo Demo"> <c:Combo_Cmpt/> </aura:application> Combo_Cmpt.cmp <aura:component implements="flexipage:availableForAllPageTypes" access="global" controller="ComboController"> <!-- ...