diff --git a/client/src/Editor.tsx b/client/src/Editor.tsx
index beae1f61..6219fa26 100644
--- a/client/src/Editor.tsx
+++ b/client/src/Editor.tsx
@@ -29,8 +29,8 @@ const Editor: React.FC<{setRestart?, onDidChangeContent?, value: string, theme:
   const [restartMessage, setRestartMessage] = useState<boolean | null>(false)
 
   useEffect(() => {
-    if (theme == 'lightPlus') {
-      monaco.editor.setTheme('lightPlus')
+    if (['lightPlus', 'custom'].includes(theme)) {
+      monaco.editor.setTheme(theme)
     } else {
       //monaco.editor.setTheme(theme)
       fetch(`./themes/${theme}.json`,{
diff --git a/client/src/Settings.tsx b/client/src/Settings.tsx
index dec255d1..f604ed82 100644
--- a/client/src/Settings.tsx
+++ b/client/src/Settings.tsx
@@ -6,7 +6,8 @@ import { useEffect } from 'react'
 import Switch from '@mui/material/Switch';
 import Select from '@mui/material/Select';
 import { useWindowDimensions } from './window_width';
-import { FormControl, InputLabel, MenuItem } from '@mui/material';
+import { Button, FormControl, InputLabel, MenuItem } from '@mui/material';
+import * as monaco from 'monaco-editor/esm/vs/editor/editor.api.js'
 
 const Settings: React.FC<{closeNav, theme, setTheme}> =
     ({closeNav, theme, setTheme}) => {
@@ -22,6 +23,7 @@ const Settings: React.FC<{closeNav, theme, setTheme}> =
     If screen width is below 800, default to vertical layout instead. */
   const {width, height} = useWindowDimensions()
   const [verticalLayout, setVerticalLayout] = React.useState(width < 800)
+  const [customTheme, setCustomTheme] = React.useState<string>('initial')
 
   // Synchronize state with initial local store
   useEffect(() => {
@@ -29,6 +31,7 @@ const Settings: React.FC<{closeNav, theme, setTheme}> =
     let _verticalLayout = window.localStorage.getItem("verticalLayout")
     let _theme = window.localStorage.getItem("theme")
     let _savingAllowed = window.localStorage.getItem("savingAllowed")
+    let _customTheme = window.localStorage.getItem("customTheme")
     if (_abbreviationCharacter) {
       setAbbreviationCharacter(_abbreviationCharacter)
       setSavingAllowed(true)
@@ -41,7 +44,18 @@ const Settings: React.FC<{closeNav, theme, setTheme}> =
       setTheme(_theme)
       setSavingAllowed(true)
     }
-
+    if (_customTheme) {
+      setCustomTheme(_customTheme)
+      setSavingAllowed(true)
+      try {
+        var loadedTheme = JSON.parse(_customTheme)
+        monaco.editor.defineTheme('custom', loadedTheme)
+      } catch (error) {
+        // invalid custom theme
+        setCustomTheme('')
+        if (_theme == 'custom') {setTheme('lightPlus')}
+      }
+    }
   }, [])
 
   /** Synchronize config and local store whenever there is a change to any of the config
@@ -55,10 +69,12 @@ const Settings: React.FC<{closeNav, theme, setTheme}> =
       window.localStorage.setItem("abbreviationCharacter", abbreviationCharacter)
       window.localStorage.setItem("verticalLayout", verticalLayout ? 'true' : 'false')
       window.localStorage.setItem("theme", theme)
+      window.localStorage.setItem("customTheme", customTheme)
     } else {
       window.localStorage.removeItem("abbreviationCharacter")
       window.localStorage.removeItem("verticalLayout")
       window.localStorage.removeItem("theme")
+      window.localStorage.removeItem("customTheme")
     }
   }, [savingAllowed, abbreviationCharacter, verticalLayout, theme])
 
@@ -75,6 +91,26 @@ const Settings: React.FC<{closeNav, theme, setTheme}> =
   //  ev.stopPropagation()
   }
 
+  /** Load a custom monaco theme, store it in local storage and activate it */
+  function uploadTheme(ev) {
+    const fileToLoad = ev.target.files[0]
+    var fileReader = new FileReader()
+    fileReader.onload = (fileLoadedEvent) => {
+      var loadedThemeRaw = fileLoadedEvent.target.result as string
+      window.localStorage.setItem("customTheme", loadedThemeRaw)
+      try {
+        var loadedTheme = JSON.parse(loadedThemeRaw)
+      } catch (error) {
+        return
+      }
+      setTheme('custom')
+      setCustomTheme(loadedThemeRaw)
+      monaco.editor.defineTheme('custom', loadedTheme)
+      monaco.editor.setTheme('custom')
+    }
+    fileReader.readAsText(fileToLoad, "UTF-8")
+  }
+
   return <>
     <span className="nav-link" onClick={handleOpen}>
       <FontAwesomeIcon icon={faGear} /> Settings
@@ -91,7 +127,7 @@ const Settings: React.FC<{closeNav, theme, setTheme}> =
               <input id="abbreviationCharacter" type="text"
                 onChange={(ev) => {setAbbreviationCharacter(ev.target.value)}} value={abbreviationCharacter} />
             </p>
-            <p>
+            <p className="flex">
               <label htmlFor="theme">Theme: </label>
               <select
                   id="theme"
@@ -102,7 +138,16 @@ const Settings: React.FC<{closeNav, theme, setTheme}> =
                 <option value="GithubDark">github dark</option>
                 <option value="Amy">amy</option>
                 <option value="Cobalt">cobalt</option>
+                <option value="custom">custom</option>
               </select>
+
+              <label htmlFor="theme-upload" className="file-upload-button" >Load from Disk</label>
+              <input id="theme-upload" type="file" onChange={uploadTheme} />
+
+              {/* <Button variant="contained" component="label" className='file-upload-button' onClick={uploadTheme}>
+                Load from Disk
+                <input id="theme-upload" type="file" onChange={uploadTheme} />
+              </Button> */}
             </p>
             <p>
               <Switch id="verticalLayout" onChange={handleLayoutChange} checked={verticalLayout} />
diff --git a/client/src/config/config.ts b/client/src/config/config.ts
index 8b625223..fd9a3773 100644
--- a/client/src/config/config.ts
+++ b/client/src/config/config.ts
@@ -7,5 +7,6 @@ export const config = {
   'inputModeCustomTranslations': {},
   'eagerReplacementEnabled': true,
   'verticalLayout': false, // value here irrelevant, will be overwritten with `width < 800` in Settings.tsx
-  'theme': 'light', // options: light, dark
+  'theme': 'lightPlus',
+  'customTheme': '',
 }
diff --git a/client/src/css/Modal.css b/client/src/css/Modal.css
index b662bfa4..7fa86a46 100644
--- a/client/src/css/Modal.css
+++ b/client/src/css/Modal.css
@@ -52,10 +52,6 @@ input[type="file"] {
   width: 100%;
 }
 
-.modal select {
-  float: right;
-}
-
 .modal textarea {
   height: 10em;
 }
@@ -65,17 +61,30 @@ input[type="file"] {
   font-weight: bold;
 }
 
-.modal input[type="submit"] {
+.modal input[type="submit"], .modal .file-upload-button {
   border: none;
   color: var(--vscode-button-foreground);
   background: var(--vscode-button-background);
   cursor: pointer;
   padding: .5rem 1rem;
   border-radius: .2rem;
+}
+
+.modal input[type="submit"]{
   display: block;
   margin: 1rem auto;
 }
 
+.modal .flex {
+  display: flex;
+  justify-content: space-between;
+}
+
+.modal .flex label {
+  margin-top: auto;
+  margin-bottom: auto;
+}
+
 .modal-close {
   float: right;
   scale: 2;