diff --git a/src/browser/public/Terminal.ts b/src/browser/public/Terminal.ts
index bd95599f96..33aa90246e 100644
--- a/src/browser/public/Terminal.ts
+++ b/src/browser/public/Terminal.ts
@@ -3,7 +3,7 @@
  * @license MIT
  */
 
-import { Terminal as ITerminalApi, ITerminalOptions, IMarker, IDisposable, ILinkMatcherOptions, ITheme, ILocalizableStrings, ITerminalAddon, ISelectionPosition, IBuffer as IBufferApi, IBufferNamespace as IBufferNamespaceApi, IBufferLine as IBufferLineApi, IBufferCell as IBufferCellApi, IParser, IFunctionIdentifier, ILinkProvider, IUnicodeHandling, IUnicodeVersionProvider } from 'xterm';
+import { Terminal as ITerminalApi, ITerminalOptions, IMarker, IDisposable, ILinkMatcherOptions, ITheme, ILocalizableStrings, ITerminalAddon, ISelectionPosition, IBuffer as IBufferApi, IBufferNamespace as IBufferNamespaceApi, IBufferLine as IBufferLineApi, IBufferCell as IBufferCellApi, IParser, IFunctionIdentifier, ILinkProvider, IUnicodeHandling, IUnicodeVersionProvider, FontWeight } from 'xterm';
 import { ITerminal } from 'browser/Types';
 import { IBufferLine, ICellData } from 'common/Types';
 import { IBuffer, IBufferSet } from 'common/buffer/Types';
@@ -169,15 +169,16 @@ export class Terminal implements ITerminalApi {
   public paste(data: string): void {
     this._core.paste(data);
   }
-  public getOption(key: 'bellSound' | 'bellStyle' | 'cursorStyle' | 'fontFamily' | 'fontWeight' | 'fontWeightBold' | 'logLevel' | 'rendererType' | 'termName' | 'wordSeparator'): string;
+  public getOption(key: 'bellSound' | 'bellStyle' | 'cursorStyle' | 'fontFamily' | 'logLevel' | 'rendererType' | 'termName' | 'wordSeparator'): string;
   public getOption(key: 'allowTransparency' | 'cancelEvents' | 'convertEol' | 'cursorBlink' | 'disableStdin' | 'macOptionIsMeta' | 'rightClickSelectsWord' | 'popOnBell' | 'visualBell'): boolean;
   public getOption(key: 'cols' | 'fontSize' | 'letterSpacing' | 'lineHeight' | 'rows' | 'tabStopWidth' | 'scrollback'): number;
+  public getOption(key: 'fontWeight' | 'fontWeightBold'): FontWeight;
   public getOption(key: string): any;
   public getOption(key: any): any {
     return this._core.optionsService.getOption(key);
   }
   public setOption(key: 'bellSound' | 'fontFamily' | 'termName' | 'wordSeparator', value: string): void;
-  public setOption(key: 'fontWeight' | 'fontWeightBold', value: 'normal' | 'bold' | '100' | '200' | '300' | '400' | '500' | '600' | '700' | '800' | '900'): void;
+  public setOption(key: 'fontWeight' | 'fontWeightBold', value: 'normal' | 'bold' | '100' | '200' | '300' | '400' | '500' | '600' | '700' | '800' | '900' | number): void;
   public setOption(key: 'logLevel', value: 'debug' | 'info' | 'warn' | 'error' | 'off'): void;
   public setOption(key: 'bellStyle', value: 'none' | 'visual' | 'sound' | 'both'): void;
   public setOption(key: 'cursorStyle', value: 'block' | 'underline' | 'bar'): void;
diff --git a/src/common/services/OptionsService.test.ts b/src/common/services/OptionsService.test.ts
index 59c17faf9e..c289b5be1d 100644
--- a/src/common/services/OptionsService.test.ts
+++ b/src/common/services/OptionsService.test.ts
@@ -19,4 +19,42 @@ describe('OptionsService', () => {
       assert.equal(new OptionsService({tabStopWidth: 0}).getOption('tabStopWidth'), DEFAULT_OPTIONS.tabStopWidth);
     });
   });
+  describe('setOption', () => {
+    let service: OptionsService;
+    beforeEach(() => {
+      service = new OptionsService({});
+    });
+    it('applies valid fontWeight option values', () => {
+      service.setOption('fontWeight', 'bold');
+      assert.equal(service.getOption('fontWeight'), 'bold', '"bold" keyword value should be applied');
+
+      service.setOption('fontWeight', 'normal');
+      assert.equal(service.getOption('fontWeight'), 'normal', '"normal" keyword value should be applied');
+
+      service.setOption('fontWeight', '600');
+      assert.equal(service.getOption('fontWeight'), '600', 'String numeric values should be applied');
+
+      service.setOption('fontWeight', 350);
+      assert.equal(service.getOption('fontWeight'), 350, 'Values between 1 and 1000 should be applied as is');
+
+      service.setOption('fontWeight', 1);
+      assert.equal(service.getOption('fontWeight'), 1, 'Range should include minimum value: 1');
+
+      service.setOption('fontWeight', 1000);
+      assert.equal(service.getOption('fontWeight'), 1000, 'Range should include maximum value: 1000');
+    });
+    it('normalizes invalid fontWeight option values', () => {
+      service.setOption('fontWeight', 350);
+      assert.doesNotThrow(() => service.setOption('fontWeight', 10000), 'fontWeight should be normalized instead of throwing');
+      assert.equal(service.getOption('fontWeight'), DEFAULT_OPTIONS.fontWeight, 'Values greater than 1000 should be reset to default');
+
+      service.setOption('fontWeight', 350);
+      service.setOption('fontWeight', -10);
+      assert.equal(service.getOption('fontWeight'), DEFAULT_OPTIONS.fontWeight, 'Values less than 1 should be reset to default');
+
+      service.setOption('fontWeight', 350);
+      service.setOption('fontWeight', 'bold700');
+      assert.equal(service.getOption('fontWeight'), DEFAULT_OPTIONS.fontWeight, 'Wrong string literals should be reset to default');
+    });
+  });
 });
diff --git a/src/common/services/OptionsService.ts b/src/common/services/OptionsService.ts
index 2f01092382..e5f6eaa8dc 100644
--- a/src/common/services/OptionsService.ts
+++ b/src/common/services/OptionsService.ts
@@ -3,7 +3,7 @@
  * @license MIT
  */
 
-import { IOptionsService, ITerminalOptions, IPartialTerminalOptions } from 'common/services/Services';
+import { IOptionsService, ITerminalOptions, IPartialTerminalOptions, FontWeight } from 'common/services/Services';
 import { EventEmitter, IEvent } from 'common/EventEmitter';
 import { isMac } from 'common/Platform';
 import { clone } from 'common/Clone';
@@ -56,6 +56,8 @@ export const DEFAULT_OPTIONS: ITerminalOptions = Object.freeze({
   cancelEvents: false
 });
 
+const FONT_WEIGHT_OPTIONS: Extract<FontWeight, string>[] = ['normal', 'bold', '100', '200', '300', '400', '500', '600', '700', '800', '900'];
+
 /**
  * The set of options that only have an effect when set in the Terminal constructor.
  */
@@ -109,14 +111,20 @@ export class OptionsService implements IOptionsService {
     switch (key) {
       case 'bellStyle':
       case 'cursorStyle':
-      case 'fontWeight':
-      case 'fontWeightBold':
       case 'rendererType':
       case 'wordSeparator':
         if (!value) {
           value = DEFAULT_OPTIONS[key];
         }
         break;
+      case 'fontWeight':
+      case 'fontWeightBold':
+        if (typeof value === 'number' && 1 <= value && value <= 1000) {
+          // already valid numeric value
+          break;
+        }
+        value = FONT_WEIGHT_OPTIONS.indexOf(value) !== -1 ? value : DEFAULT_OPTIONS[key];
+        break;
       case 'cursorWidth':
         value = Math.floor(value);
         // Fall through for bounds check
diff --git a/src/common/services/Services.ts b/src/common/services/Services.ts
index 19a34d19f5..0ea7a30804 100644
--- a/src/common/services/Services.ts
+++ b/src/common/services/Services.ts
@@ -179,7 +179,7 @@ export interface IOptionsService {
   getOption<T>(key: string): T | undefined;
 }
 
-export type FontWeight = 'normal' | 'bold' | '100' | '200' | '300' | '400' | '500' | '600' | '700' | '800' | '900';
+export type FontWeight = 'normal' | 'bold' | '100' | '200' | '300' | '400' | '500' | '600' | '700' | '800' | '900' | number;
 export type LogLevel = 'debug' | 'info' | 'warn' | 'error' | 'off';
 export type RendererType = 'dom' | 'canvas';
 
diff --git a/typings/xterm.d.ts b/typings/xterm.d.ts
index f98c629d76..1fc0c853ba 100644
--- a/typings/xterm.d.ts
+++ b/typings/xterm.d.ts
@@ -11,9 +11,9 @@
 
 declare module 'xterm' {
   /**
-   * A string representing text font weight.
+   * A string or number representing text font weight.
    */
-  export type FontWeight = 'normal' | 'bold' | '100' | '200' | '300' | '400' | '500' | '600' | '700' | '800' | '900';
+  export type FontWeight = 'normal' | 'bold' | '100' | '200' | '300' | '400' | '500' | '600' | '700' | '800' | '900' | number;
 
   /**
    * A string representing log level.
@@ -933,7 +933,7 @@ declare module 'xterm' {
      * Retrieves an option's value from the terminal.
      * @param key The option key.
      */
-    getOption(key: 'bellSound' | 'bellStyle' | 'cursorStyle' | 'fontFamily' | 'fontWeight' | 'fontWeightBold' | 'logLevel' | 'rendererType' | 'termName' | 'wordSeparator'): string;
+    getOption(key: 'bellSound' | 'bellStyle' | 'cursorStyle' | 'fontFamily' | 'logLevel' | 'rendererType' | 'termName' | 'wordSeparator'): string;
     /**
      * Retrieves an option's value from the terminal.
      * @param key The option key.
@@ -944,6 +944,11 @@ declare module 'xterm' {
      * @param key The option key.
      */
     getOption(key: 'cols' | 'fontSize' | 'letterSpacing' | 'lineHeight' | 'rows' | 'tabStopWidth' | 'scrollback'): number;
+    /**
+     * Retrieves an option's value from the terminal.
+     * @param key The option key.
+     */
+    getOption(key: 'fontWeight' | 'fontWeightBold'): FontWeight;
     /**
      * Retrieves an option's value from the terminal.
      * @param key The option key.
@@ -961,7 +966,7 @@ declare module 'xterm' {
     * @param key The option key.
     * @param value The option value.
     */
-    setOption(key: 'fontWeight' | 'fontWeightBold', value: null | 'normal' | 'bold' | '100' | '200' | '300' | '400' | '500' | '600' | '700' | '800' | '900'): void;
+    setOption(key: 'fontWeight' | 'fontWeightBold', value: null | 'normal' | 'bold' | '100' | '200' | '300' | '400' | '500' | '600' | '700' | '800' | '900' | number): void;
     /**
     * Sets an option on the terminal.
     * @param key The option key.