diff --git a/doc/vscode-texinfo.texi b/doc/vscode-texinfo.texi
index 4fd258b..d7042fe 100644
--- a/doc/vscode-texinfo.texi
+++ b/doc/vscode-texinfo.texi
@@ -457,6 +457,8 @@ are not validated. (@code{--no-validate})
 @item @code{texinfo.preview.variables}: Array of variables to define (as with
 @code{@@set}). If a variable has a value, use the ASCII space character to
 separate key and value.
+@item @code{texinfo.preview.customizationVariables}: Array of customization
+variables. (@code{-c KEY=VALUE})
 @end itemize
 
 
diff --git a/package.json b/package.json
index 7157876..73be267 100644
--- a/package.json
+++ b/package.json
@@ -207,6 +207,11 @@
                     "type": "array",
                     "default": [],
                     "description": "Define variables (as with @set)."
+                },
+                "texinfo.preview.customizationVariables": {
+                    "type": "array",
+                    "default": [],
+                    "description": "Set customization variables (format: KEY=VAL)"
                 }
             }
         },
diff --git a/src/options.ts b/src/options.ts
index 565c475..755b4b8 100644
--- a/src/options.ts
+++ b/src/options.ts
@@ -80,6 +80,10 @@ export default class Options
         return this._getArray('preview.variables');
     }
 
+    get customizationVariables() {
+        return this._getArray('preview.customizationVariables');
+    }
+
     private readonly _configuration
         = vscode.workspace.getConfiguration('texinfo');
 
diff --git a/src/utils/converter.ts b/src/utils/converter.ts
index 66904d4..040110f 100644
--- a/src/utils/converter.ts
+++ b/src/utils/converter.ts
@@ -48,6 +48,8 @@ export default class Converter
         }
         this._addIncludePaths(this._options.includePaths, options);
         this._defineVariables(this._options.variables, options);
+        this._setCustomizationVariables(
+            this._options.customizationVariables, options);
         this._includeCustomCSS(this._options.customCSS, options);
         return await exec(
             this._options.makeinfo,
@@ -75,6 +77,13 @@ export default class Converter
         variables.forEach(varName => options.push('-D', varName));
     }
 
+    private _setCustomizationVariables(
+        variables: readonly string[],
+        options: string[],
+    ) {
+        variables.forEach(varName => options.push('-c', varName));
+    }
+
     private _includeCustomCSS(cssFileURI: string, options: string[]) {
         if (!cssFileURI) {
             return;