Do We Need A Namespace To Develop Salesforce Lightning Components?

Hi,

No. Lightning Components used to require a namespace, but that is no longer a requirement.

Hope this helps.

Addin some more points:

Namespace prefixes are used in managed Force.com AppExchange packages to differentiate custom object and field names from those in use by other organizations.

Example:

your field name - test__c

and your Namespace name is "app" then resultant field name will be "app__test__c".

It is a very useful feature so that the API name of the Managed package should not conflict with native fields API Name.