A liquid crystal aligning agent composition comprising: a polymer which includes one or more selected from the group consisting of a polyamic acid repeating unit, a polyamic acid ester repeating unit, and a polyimide repeating unit, and has a primary amino group bonded to at least one terminal; and a terminal modifier compound represented by the following Chemical Formula 1, wherein, in Chemical Formula 1, R 1 is either one of a linear organic functional group represented by the following Chemical Formula 2 and a cyclic organic functional group represented by the following Chemical Formula 3, wherein, in Chemical Formula 2, R 2 is any one of -O-, -CO-, -S-, -CONH-, -COO-, -O(CH 2) z O-, -OCO-(CH 2) z -OCO-, a substituted or unsubstituted alkylene group having 1 to 20 carbon atoms, and a substituted or unsubstituted alkenylene group having 2 to 20 carbon atoms, and Z is an integer of 1 to 10, wherein, in Chemical Formula 3, C 1 is any one of a substituted or unsubstituted cycloalkylene group having 3 to 20 carbon atoms, a substituted or unsubstituted arylene group having 6 to 20 carbon atoms, a substituted or unsubstituted heteroarylene group having 4 to 20 carbon atoms, and a substituted or unsubstituted cycloalkenylene group having 3 to 20 carbon atoms, wherein the polyimide repeating unit includes a repeating unit represented by the following Chemical Formula 4, the polyamic acid ester repeating unit includes a repeating unit represented by the following Chemical Formula 5, and the polyamic acid repeating unit includes a repeating unit represented by the following Chemical Formula 6: wherein, in Chemical Formulas 4 to 6, at least one of R 3 and R 4 is an alkyl having 1 to 10 carbon atoms and the rest are hydrogen, X 1 to X 3 are the same as or different from each other, and are each independently a tetravalent organic group, Y 1 to Y 3 are the same as or different from each other, and are each independently a divalent organic group represented by the following Chemical Formula 7, wherein, in Chemical Formula 7, at least one of Q 1 to Q 8 is nitrogen and the rest are carbon, D is -NR'- or -O-, and R' is hydrogen or an alkyl group having 1 to 6 carbon atoms. a polymer which includes one or more selected from the group consisting of a polyamic acid repeating unit, a polyamic acid ester repeating unit, and a polyimide repeating unit, and has a primary amino group bonded to at least one terminal; and a terminal modifier compound represented by the following Chemical Formula 1, wherein, in Chemical Formula 1, R 1 is either one of a linear organic functional group represented by the following Chemical Formula 2 and a cyclic organic functional group represented by the following Chemical Formula 3, wherein, in Chemical Formula 2, R 2 is any one of -O-, -CO-, -S-, -CONH-, -COO-, -O(CH 2) z O-, -OCO-(CH 2) z -OCO-, a substituted or unsubstituted alkylene group having 1 to 20 carbon atoms, and a substituted or unsubstituted alkenylene group having 2 to 20 carbon atoms, and Z is an integer of 1 to 10, wherein, in Chemical Formula 3, C 1 is any one of a substituted or unsubstituted cycloalkylene group having 3 to 20 carbon atoms, a substituted or unsubstituted arylene group having 6 to 20 carbon atoms, a substituted or unsubstituted heteroarylene group having 4 to 20 carbon atoms, and a substituted or unsubstituted cycloalkenylene group having 3 to 20 carbon atoms, wherein the polyimide repeating unit includes a repeating unit represented by the following Chemical Formula 4, the polyamic acid ester repeating unit includes a repeating unit represented by the following Chemical Formula 5, and the polyamic acid repeating unit includes a repeating unit represented by the following Chemical Formula 6: wherein, in Chemical Formulas 4 to 6, at least one of R 3 and R 4 is an alkyl having 1 to 10 carbon atoms and the rest are hydrogen, X 1 to X 3 are the same as or different from each other, and are each independently a tetravalent organic group, Y 1 to Y 3 are the same as or different from each other, and are each independently a divalent organic group represented by the following Chemical Formula 7, wherein, in Chemical Formula 7, at least one of Q 1 to Q 8 is nitrogen and the rest are carbon, D is -NR'- or -O-, and R' is hydrogen or an alkyl group having 1 to 6 carbon atoms. at least one of R 3 and R 4 is an alkyl having 1 to 10 carbon atoms and the rest are hydrogen, X 1 to X 3 are the same as or different from each other, and are each independently a tetravalent organic group, Y 1 to Y 3 are the same as or different from each other, and are each independently a divalent organic group represented by the following Chemical Formula 7,