Is my military pension/retirement income taxable to Montana? According to the Montana Department of Revenue, military retirement is fully taxable on your Montana return to the extent that is reported on your federal return. Start for $0 today Get your maximum refund with all the deductions and credits you deserve Get Started Login Related articles Is my military pension/retirement income taxable to Nebraska? Do I Owe Mississippi Use Tax? What Payments can I list on my Montana return? How much can I contribute to an SEP? What's New in 2020 for Kansas?