diff --git a/javascript/MaterialXView/source/dropHandling.js b/javascript/MaterialXView/source/dropHandling.js
new file mode 100644
index 0000000000..adcbef2ca1
--- /dev/null
+++ b/javascript/MaterialXView/source/dropHandling.js
@@ -0,0 +1,281 @@
+import * as THREE from 'three';
+import * as fflate from 'three/examples/jsm/libs/fflate.module.js';
+
+const debugFileHandling = false;
+let loadingCallback;
+
+export function setLoadingCallback(cb) {
+    loadingCallback = cb;
+}
+
+export function dropHandler(ev) {
+    if (debugFileHandling) console.log('File(s) dropped', ev.dataTransfer.items, ev.dataTransfer.files);
+
+    // Prevent default behavior (Prevent file from being opened)
+    ev.preventDefault();
+
+    if (ev.dataTransfer.items)
+    {
+        const allEntries = [];
+
+        let haveGetAsEntry = false;
+        if (ev.dataTransfer.items.length > 0)
+        haveGetAsEntry = 
+            ("getAsEntry" in ev.dataTransfer.items[0]) || 
+            ("webkitGetAsEntry" in ev.dataTransfer.items[0]);
+
+        // Useful for debugging file handling on platforms that don't support newer file system APIs
+        // haveGetAsEntry = false;
+
+        if (haveGetAsEntry) {
+            for (var i = 0; i < ev.dataTransfer.items.length; i++)
+            {
+                let item = ev.dataTransfer.items[i];
+                let entry = ("getAsEntry" in item) ? item.getAsEntry() : item.webkitGetAsEntry();
+                allEntries.push(entry);
+            }
+            handleFilesystemEntries(allEntries);
+            return;
+        }
+
+        for (var i = 0; i < ev.dataTransfer.items.length; i++)
+        {
+            let item = ev.dataTransfer.items[i];
+            
+            // API when there's no "getAsEntry" support
+            console.log(item.kind, item);
+            if (item.kind === 'file')
+            {
+                var file = item.getAsFile();
+                testAndLoadFile(file);
+            }
+            // could also be a directory
+            else if (item.kind === 'directory')
+            {
+                var dirReader = item.createReader();
+                dirReader.readEntries(function(entries) {
+                for (var i = 0; i < entries.length; i++) {
+                    console.log(entries[i].name);
+                    var entry = entries[i];
+                    if (entry.isFile) {
+                    entry.file(function(file) {
+                        testAndLoadFile(file);
+                    });
+                    }
+                }
+                });
+            }
+        }
+    } else {
+        for (var i = 0; i < ev.dataTransfer.files.length; i++) {
+            let file = ev.dataTransfer.files[i];
+            testAndLoadFile(file);
+        }
+    }
+}
+
+export function dragOverHandler(ev) {
+    ev.preventDefault();
+}
+
+async function getBufferFromFile(fileEntry) {
+
+    if (fileEntry instanceof ArrayBuffer) return fileEntry;
+    if (fileEntry instanceof String) return fileEntry;
+
+    const name = fileEntry.fullPath || fileEntry.name;
+    const ext = name.split('.').pop();
+    const readAsText = ext === 'mtlx';
+
+    if (debugFileHandling) console.log("reading ", fileEntry, "as text?", readAsText);
+
+    if (debugFileHandling) console.log("getBufferFromFile", fileEntry);
+    const buffer = await new Promise((resolve, reject) => {
+        function readFile(file) {
+            var reader = new FileReader();
+            reader.onloadend = function(e) {
+                if (debugFileHandling) console.log("loaded", "should be text?", readAsText, this.result);
+                resolve(this.result);
+            };
+            
+            if (readAsText)
+                reader.readAsText(file);
+            else
+                reader.readAsArrayBuffer(file);
+        }
+
+        if ("file" in fileEntry) {
+            fileEntry.file(function(file) {
+                readFile(file);
+            }, (e) => {
+                console.error("Error reading file ", e);
+            });
+        }
+        else {
+            readFile(fileEntry);
+        }
+    });
+    return buffer;
+}
+
+async function handleFilesystemEntries(entries) {
+    const allFiles = [];
+    const fileIgnoreList = [
+      '.gitignore',
+      'README.md',
+      '.DS_Store',
+    ]
+    const dirIgnoreList = [
+      '.git',
+      'node_modules',
+    ]
+
+    for (let entry of entries) {
+      if (debugFileHandling) console.log("file entry", entry)
+      if (entry.isFile) {
+        if (debugFileHandling) console.log("single file", entry);
+        if (fileIgnoreList.includes(entry.name)) {
+          continue;
+        }
+        allFiles.push(entry);
+      }
+      else if (entry.isDirectory) {
+        if (dirIgnoreList.includes(entry.name)) {
+          continue;
+        }
+        const files = await readDirectory(entry);
+        if (debugFileHandling) console.log("all files", files);
+        for (const file of files) {
+          if (fileIgnoreList.includes(file.name)) {
+            continue;
+          }
+          allFiles.push(file);
+        }
+      }
+    }
+
+    const imageLoader = new THREE.ImageLoader();
+
+    // unpack zip files first
+    for (const fileEntry of allFiles) {
+        // special case: zip archives
+        if (fileEntry.fullPath.toLowerCase().endsWith('.zip')) {
+            await new Promise(async (resolve, reject) => {
+                const arrayBuffer = await getBufferFromFile(fileEntry);
+
+                // use fflate to unpack them and add the files to the cache
+                fflate.unzip(new Uint8Array(arrayBuffer), (error, unzipped) => {
+                    // push these files into allFiles
+                    for (const [filePath, buffer] of Object.entries(unzipped)) {
+
+                        // mock FileEntry for easier usage downstream
+                        const blob = new Blob([buffer]);
+                        const newFileEntry = {
+                            fullPath: "/" + filePath,
+                            name: filePath.split('/').pop(),
+                            file: (callback) => {
+                                callback(blob);
+                            },
+                            isFile: true,
+                        };
+                        allFiles.push(newFileEntry);
+                    }
+
+                    resolve();
+                });
+            });
+        }
+    }
+
+    // sort so mtlx files come first
+    allFiles.sort((a, b) => {
+        if (a.name.endsWith('.mtlx') && !b.name.endsWith('.mtlx')) {
+            return -1;
+        }
+        if (!a.name.endsWith('.mtlx') && b.name.endsWith('.mtlx')) {
+            return 1;
+        }
+        return 0;
+    });
+
+    if (debugFileHandling) console.log("all files", allFiles);
+
+    // put all files in three' Cache
+    for (const fileEntry of allFiles) {
+
+        const allowedFileTypes = [
+            'png', 'jpg', 'jpeg'
+        ];
+
+        const ext = fileEntry.fullPath.split('.').pop();
+        if (!allowedFileTypes.includes(ext)) {
+            // console.log("skipping file", fileEntry.fullPath);
+            continue;
+        }
+
+        const buffer = await getBufferFromFile(fileEntry);
+        const img = await imageLoader.loadAsync(URL.createObjectURL(new Blob([buffer])));
+        if (debugFileHandling) console.log("caching file", fileEntry.fullPath, img);
+        THREE.Cache.add(fileEntry.fullPath, img);
+    }
+
+    // TODO we could also allow dropping of multiple MaterialX files (or folders with them inside) 
+    // and seed the dropdown from that.
+    // At that point, actually reading files and textures into memory should be deferred until they are actually used.
+    const rootFile = allFiles[0];
+    THREE.Cache.add(rootFile.fullPath, await getBufferFromFile(rootFile));
+
+    if (debugFileHandling) console.log("CACHE", THREE.Cache.files);
+
+    loadingCallback(rootFile);
+}
+
+async function readDirectory(directory) {
+    let entries = [];
+    let getEntries = async (directory) => {
+        let dirReader = directory.createReader();
+        await new Promise((resolve, reject) => {
+        dirReader.readEntries(
+            async (results) => {
+            if (results.length) {
+                // entries = entries.concat(results);
+                for (let entry of results) {
+                if (entry.isDirectory) {
+                    await getEntries(entry);
+                }
+                else {
+                    entries.push(entry);
+                }
+                }
+            }
+            resolve();
+            },
+            (error) => {
+                /* handle error — error is a FileError object */
+            },
+        )}
+    )};
+
+    await getEntries(directory);
+    return entries;
+}
+
+async function testAndLoadFile(file) {
+    let ext = file.name.split('.').pop();
+    if (debugFileHandling) console.log(file.name + ", " + file.size + ", " + ext);
+
+    const arrayBuffer = await getBufferFromFile(file);
+    console.log(arrayBuffer)
+
+    // mock a fileEntry and pass through the same loading logic
+    const newFileEntry = {
+        fullPath: "/" + file.name,
+        name: file.name.split('/').pop(),
+        isFile: true,
+        file: (callback) => {
+            callback(file);
+        }
+    };
+
+    handleFilesystemEntries([newFileEntry]);
+}
\ No newline at end of file
diff --git a/javascript/MaterialXView/source/index.js b/javascript/MaterialXView/source/index.js
index 424f63ec43..56e2e1f5a2 100644
--- a/javascript/MaterialXView/source/index.js
+++ b/javascript/MaterialXView/source/index.js
@@ -12,6 +12,7 @@ import { ShaderPass } from 'three/examples/jsm/postprocessing/ShaderPass.js';
 import { GammaCorrectionShader } from 'three/examples/jsm/shaders/GammaCorrectionShader.js';
 
 import { Viewer } from './viewer.js'
+import { dropHandler, dragOverHandler, setLoadingCallback } from './dropHandling.js';
 
 let renderer, composer, orbitControls;
 
@@ -115,6 +116,20 @@ function init()
         console.error(Number.isInteger(err) ? this.getMx().getExceptionMessage(err) : err);
     })
 
+    // allow dropping files and directories
+    document.addEventListener('drop', dropHandler, false);
+    document.addEventListener('dragover', dragOverHandler, false);
+
+    setLoadingCallback(file => {
+        materialFilename = file.fullPath || file.name;
+        viewer.getEditor().clearFolders();
+        viewer.getMaterial().loadMaterials(viewer, materialFilename);
+        viewer.getEditor().updateProperties(0.9);
+        viewer.getScene().setUpdateTransforms();
+    });
+
+    // enable three.js Cache so that dropped files can reference each other
+    THREE.Cache.enabled = true;
 }
 
 function onWindowResize() 
diff --git a/javascript/MaterialXView/source/viewer.js b/javascript/MaterialXView/source/viewer.js
index 0bc537faf0..d1adfd9ef4 100644
--- a/javascript/MaterialXView/source/viewer.js
+++ b/javascript/MaterialXView/source/viewer.js
@@ -589,6 +589,7 @@ export class Material
 
         // Set search path. Assumes images are relative to current file
         // location.
+        if (!materialFilename) materialFilename = "/";
         const paths = materialFilename.split('/');
         paths.pop(); 
         const searchPath = paths.join('/');