How has this not been added yet? This should be a key feature.

I am surprised this hasn't been implemented yet, this would help most of Jira's customers. Please get onto it Team Jira!

Having the capability to assign a single card to multiple people on our line would be a huge benefit when it comes to paired programming and the management of cards within Jira. 

We need this feature, not only from a paired-programming standpoint, but also during times of resources being out of office and someone else picks up the work for a period of time, when needed.

This functionality would be incredibly helpful to my line due to sometimes having different capability changes (needing 2 different resources) on one defect fix as well as paired programming.  

Paired programming is a fundamental practice/technique with Agile and one that my team utilizes consistently.  Having to create separate cards for each developer or sub-tasks is an administrative nightmare, especially when working on larger initiatives.  Additionally, not having the ability to assign multiple users to a card results in resources charging their time against other efforts the line is working on rather than the effort for which they did work (i.e. agile costing) that then requires manual adjustments to timesheets every month.  Allowing multiple assignees would ensure that the individuals are recognized for the work that they are doing.

Pairing is an essential part of my team's success.  Being able to assign multiple people would alleviate the extra administrative work we have to do by creating cards.  

This is a critical component to making Agile Costing more directionally correct.

While we encourage pairing as a fundamental practice in Agile, the limitation with Jira is not allowing it for costing purposes. I would highly vote for this change.

This isn't just something cool to have.  This should be foundational.  Pairing is an agile foundational concept and it would great if our workflow tools supported those concepts as built-in functionality.  Creating duplicate cards or needing custom fields (that aren't then available in JQL) to manage work is wasteful causes a host of other problems.