diff --git a/crates/cli-support/src/js/mod.rs b/crates/cli-support/src/js/mod.rs
index 614a5d12278..aafb1c2fe26 100644
--- a/crates/cli-support/src/js/mod.rs
+++ b/crates/cli-support/src/js/mod.rs
@@ -339,7 +339,7 @@ impl<'a> Context<'a> {
         module_name: &str,
         needs_manual_start: bool,
     ) -> Result<(String, String, Option<String>), Error> {
-        let mut ts = self.typescript.clone();
+        let mut ts;
         let mut js = String::new();
         let mut start = None;
 
@@ -441,6 +441,16 @@ impl<'a> Context<'a> {
             }
         }
 
+        // Before putting the static init code declaration info, put all existing typescript into a `wasm_bindgen` namespace declaration.
+        // Not sure if this should happen in all cases, so just adding it to NoModules for now...
+        if self.config.mode.no_modules() {
+            ts = String::from("declare namespace wasm_bindgen {\n\t");
+            ts.push_str(&self.typescript.replace("\n", "\n\t"));
+            ts.push_str("\n}\n");
+        } else {
+            ts = self.typescript.clone();
+        }
+
         let (init_js, init_ts) = init;
 
         ts.push_str(&init_ts);
@@ -556,11 +566,23 @@ impl<'a> Context<'a> {
             ("", "")
         };
         let arg_optional = if has_module_or_path_optional { "?" } else { "" };
+        // With TypeScript 3.8.3, I'm seeing that any "export"s at the root level cause TypeScript to ignore all "declare" statements.
+        // So using "declare" everywhere for at least the NoModules option.
+        // Also in (at least) the NoModules, the `init()` method is renamed to `wasm_bindgen()`.
+        let setup_function_declaration;
+        let declare_or_export;
+        if self.config.mode.no_modules() {
+            declare_or_export = "declare";
+            setup_function_declaration = "declare function wasm_bindgen";
+        } else {
+            declare_or_export = "export";
+            setup_function_declaration = "export default function init";
+        }
         Ok(format!(
             "\n\
-            export type InitInput = RequestInfo | URL | Response | BufferSource | WebAssembly.Module;\n\
+            {declare_or_export} type InitInput = RequestInfo | URL | Response | BufferSource | WebAssembly.Module;\n\
             \n\
-            export interface InitOutput {{\n\
+            {declare_or_export} interface InitOutput {{\n\
             {output}}}\n\
             \n\
             /**\n\
@@ -572,11 +594,12 @@ impl<'a> Context<'a> {
             *\n\
             * @returns {{Promise<InitOutput>}}\n\
             */\n\
-            export default function init \
-                (module_or_path{}: InitInput | Promise<InitInput>{}): Promise<InitOutput>;
-        ",
+            {setup_function_declaration} \
+                (module_or_path{}: InitInput | Promise<InitInput>{}): Promise<InitOutput>;\n",
             memory_doc, arg_optional, memory_param,
             output = output,
+            declare_or_export = declare_or_export,
+            setup_function_declaration = setup_function_declaration,
         ))
     }
 
diff --git a/crates/typescript-tests/.gitignore b/crates/typescript-tests/.gitignore
index 2dfbe6f5bc4..834c04dd11a 100644
--- a/crates/typescript-tests/.gitignore
+++ b/crates/typescript-tests/.gitignore
@@ -1,2 +1,4 @@
 pkg
 dist
+src_no_modules
+dist_no_modules
diff --git a/crates/typescript-tests/no_modules.tsconfig.json b/crates/typescript-tests/no_modules.tsconfig.json
new file mode 100644
index 00000000000..e3688b7d156
--- /dev/null
+++ b/crates/typescript-tests/no_modules.tsconfig.json
@@ -0,0 +1,12 @@
+{
+    "compilerOptions": {
+        "target": "es6",
+        "noImplicitAny": true,
+        "sourceMap": true,
+        "outDir": "dist_no_modules",
+    },
+    "include": [
+        "pkg/no_modules/*.d.ts",
+        "src_no_modules/*.ts",
+    ]
+}
diff --git a/crates/typescript-tests/run.sh b/crates/typescript-tests/run.sh
index 95a868a58e6..f971f251bf2 100755
--- a/crates/typescript-tests/run.sh
+++ b/crates/typescript-tests/run.sh
@@ -23,3 +23,37 @@ if [ ! -d node_modules ]; then
 fi
 
 npm run tsc
+
+# Build using no-modules.
+mkdir pkg/no_modules
+cargo run -p wasm-bindgen-cli --bin wasm-bindgen -- \
+  ../../target/wasm32-unknown-unknown/debug/typescript_tests.wasm \
+  --out-dir pkg/no_modules \
+  --target no-modules \
+  --typescript
+
+# Then create copies of the TypeScript tests used on "--target web" (i.e. those in ./src) but adjust them to work with "--target no-modules".
+# Store the new generated test files under "src_no_modules".
+rm -rf src_no_modules
+mkdir src_no_modules
+cd src
+for filename in *.ts; do
+  if grep -q "_bg.wasm" "$filename"
+  then
+    # I am unsure how to import or test the "*_bg.wasm" file.
+    # So any test file that includes those is currently being skipped.
+    echo "Ignoring $filename as it uses the *.wasm.d.ts file."
+  else
+    path="../src_no_modules/$filename"
+    # Copy over every line EXCEPT for the import statements (since "no-modules" has no modules to import).
+    grep -v -w "import" "$filename" > "$path"
+    # Then replace all of the instances of "wbg" (the namespace all the tests use to import the *.d.ts files from "--target web") with "wasm_bindgen" (the namespace the `no-modules` *.d.ts files use).
+    sed -i "s/wbg\./wasm_bindgen./g" "$path"
+    sed -i "s/wbg /wasm_bindgen /g" "$path"
+    sed -i "s/wbg\[/wasm_bindgen[/g" "$path"
+  fi
+done
+cd ..
+
+# Then try to build the typescript in the src_no_modules folder against the pkg/no_modules build.
+npm run tsc -- -p no_modules.tsconfig.json