To amend the Internal Revenue Code of 1986 to allow members of the Ready Reserve of a reserve component of the Armed Forces to make elective deferrals on the basis of their service to the Ready Reserve and on the basis of their other employment.

Servicemember Retirement Improvement Act This bill amends the Internal Revenue Code to allow members of the Ready Reserve of a reserve component of the Armed Forces to make the maximum allowable contribution ($18,000 in 2017) to their Thrift Savings Plans (TSPs) without limiting the amount such members may contribute to a retirement plan based upon other employment. The bill also doubles the maximum allowable contribution amount to the TSPs of federal employees in the Ready Reserve who are not eligible to make contributions to any plan other than the TSP.