If I am a US citizen and live/work in a foreign country with annual income below the Foreign Earned Income Exclusion maximum, can I make contributions to a Roth IRA?

[DS30]

It depends but if you have no other taxable income after claiming the foreign earned income exclusion (FEIE) then you will not be able to make a contribute to a Roth IRA. The IRS rule on IRA contributions is -  a person cannot contribute excluded income to an IRA.

However, if you have any other compensation income not related to your FEIE, then you can contribute up to your other taxable compensation income or the $5,500 limit but you will need to add back in the excluded foreign earned income in order to determine your modified AGI and see if you are still eligible to make any Roth IRA contribution.

Please refer to IRS - Roth IRAs - Publication 590 for more information about Roth IRAs.

[edited 2/23/2018 - 2:51 PM PST]

[dmertz]

Specifically, you need other *compensation* not excluded under the FEIE, not just other income.  If all of your compensation is excluded under the FEIE, you are ineligible to contribute to an IRA regardless of what other income you have.

[DS30]

Please see updated answer.