jats:titleAbstract</jats:title> jats:pWe present the discovery of VVV J165507.19−421755.5, a mid-T dwarf found through ongoing unWISE-based proper motion searches. A near-infrared spectrum of this object obtained with the NIRES instrument on the Keck II telescope indicates a spectral classification of T5. Using data from the VISTA Variables in the Via Lactea (VVV) catalog with a 9 year baseline, we measure a proper motion of (jats:inline-formula jats:tex-math

</jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> mml:msub mml:mrow mml:miμ</mml:mi> </mml:mrow> mml:mrow mml:miα</mml:mi> </mml:mrow> </mml:msub> mml:micos</mml:mi> <mml:mo stretchy="true">(</mml:mo> mml:miδ</mml:mi> <mml:mo stretchy="true">)</mml:mo> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="rnaasac9141ieqn1.gif" xlink:type="simple"/> </jats:inline-formula>, jats:italicμ</jats:italic> jats:sub jats:italicδ</jats:italic> </jats:sub>) = (−631.0 ± 1.3, −315.0 ± 1.4) mas yrjats:sup−1</jats:sup> and a trigonometric parallax of jats:italicπ</jats:italic> jats:subabs</jats:sub> = 66.0 ± 4.8 mas, corresponding to a distance of 15.2 ± 1.1 pc. The trigonometric parallax agrees well with our photometric distance estimate (16.1jats:inline-formula jats:tex-math

</jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> mml:msubsup mml:mrow/ mml:mrow mml:mo−</mml:mo> mml:mn3.9</mml:mn> </mml:mrow> mml:mrow mml:mo+</mml:mo> mml:mn5.1</mml:mn> </mml:mrow> </mml:msubsup> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="rnaasac9141ieqn2.gif" xlink:type="simple"/> </jats:inline-formula> pc) assuming that VVV J165507.19−421755.5 is a single T5 dwarf. VVV J165507.19−421755.5 is a new member of the 20 parsec census.</jats:p>