I am following the documentation of https://material.angular.io/guide/theming#defining-a-theme // From documentation $theme: mat.define-theme(( typography: ( brand-family: 'Open Sans', bold-weight: 900 ), )); html { @include mat.core-theme($theme); @include mat.all-component-themes($theme); @include mat.all-component-typographies($theme); } and tried the answer from Font-Family Change on Angular Material // Answer based on stackoverflow $my-theme: mat.define-theme($config: ( typography: ( plain-family: '"Open Sans", sans-serif', brand-family: '"Open Sans", sans-serif', ), ),); :root { @include mat.all-component-typographies($my-theme); } none of the options worked. Let me know how to change the font family on material v18 PS: Do not comment there are already answers. Those are for previous versions which do not work for v18 Continue reading...