The first search for scalar leptoquarks produced in <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:mi>τ</a:mi></a:math>-lepton–quark collisions is presented. It is based on a set of proton-proton collision data recorded with the CMS detector at the LHC at a center-of-mass energy of 13 TeV corresponding to an integrated luminosity of <c:math xmlns:c="http://www.w3.org/1998/Math/MathML" display="inline"><c:mrow><c:mn>138</c:mn><c:mtext> </c:mtext><c:mtext> </c:mtext><c:msup><c:mrow><c:mi>fb</c:mi></c:mrow><c:mrow><c:mo>−</c:mo><c:mn>1</c:mn></c:mrow></c:msup></c:mrow></c:math>. The reconstructed final state consists of a jet, significant missing transverse momentum, and a <e:math xmlns:e="http://www.w3.org/1998/Math/MathML" display="inline"><e:mi>τ</e:mi></e:math> lepton reconstructed through its hadronic or leptonic decays. Limits are set on the product of the leptoquark production cross section and branching fraction and interpreted as exclusions in the plane of the leptoquark mass and the leptoquark-<g:math xmlns:g="http://www.w3.org/1998/Math/MathML" display="inline"><g:mi>τ</g:mi></g:math>-quark coupling strength. © 2024 CERN, for the CMS Collaboration 2024 CERN