diff --git a/src/index.js b/src/index.js
index bfa22496..cdc00a56 100644
--- a/src/index.js
+++ b/src/index.js
@@ -482,8 +482,8 @@ function createConfig(options, entry, format, writeMeta) {
 		if (name instanceof RegExp) name = name.source;
 
 		// valid JS identifiers are usually library globals:
-		if (name.match(/^[a-z_$][a-z0-9_$]*$/)) {
-			globals[name] = name;
+		if (name.match(/^[a-z_$][a-z0-9_\-$]*$/)) {
+			globals[name] = camelCase(name);
 		}
 		return globals;
 	}, {});
diff --git a/test/__snapshots__/index.test.js.snap b/test/__snapshots__/index.test.js.snap
index 9356d961..0fab5d8a 100644
--- a/test/__snapshots__/index.test.js.snap
+++ b/test/__snapshots__/index.test.js.snap
@@ -428,6 +428,54 @@ exports[`fixtures build basic-css with microbundle 6`] = `
 "
 `;
 
+exports[`fixtures build basic-dashed-external with microbundle 1`] = `
+"Used script: microbundle
+
+Directory tree:
+
+basic-dashed-external
+  dist
+    basic-dashed-external.esm.js
+    basic-dashed-external.esm.js.map
+    basic-dashed-external.js
+    basic-dashed-external.js.map
+    basic-dashed-external.umd.js
+    basic-dashed-external.umd.js.map
+  package.json
+  src
+    index.js
+    two.js
+
+
+Build \\"basicDashedExternal\\" to dist:
+248 B: basic-dashed-external.js.gz
+188 B: basic-dashed-external.js.br
+214 B: basic-dashed-external.esm.js.gz
+164 B: basic-dashed-external.esm.js.br
+349 B: basic-dashed-external.umd.js.gz
+281 B: basic-dashed-external.umd.js.br"
+`;
+
+exports[`fixtures build basic-dashed-external with microbundle 2`] = `6`;
+
+exports[`fixtures build basic-dashed-external with microbundle 3`] = `
+"import r from\\"tiny-glob\\";var e=function(){try{var r=arguments;return Promise.resolve([].slice.call(r).reduce(function(r,e){return r+e},0))}catch(r){return Promise.reject(r)}};console.log(r);export default function(){try{var r=arguments,t=[].slice.call(r);return Promise.resolve(e.apply(void 0,t)).then(function(r){return Promise.resolve(e.apply(void 0,t)).then(function(e){return[r,e]})})}catch(r){return Promise.reject(r)}}
+//# sourceMappingURL=basic-dashed-external.esm.js.map
+"
+`;
+
+exports[`fixtures build basic-dashed-external with microbundle 4`] = `
+"var e,r=(e=require(\\"tiny-glob\\"))&&\\"object\\"==typeof e&&\\"default\\"in e?e.default:e,t=function(){try{var e=arguments;return Promise.resolve([].slice.call(e).reduce(function(e,r){return e+r},0))}catch(e){return Promise.reject(e)}};console.log(r),module.exports=function(){try{var e=arguments,r=[].slice.call(e);return Promise.resolve(t.apply(void 0,r)).then(function(e){return Promise.resolve(t.apply(void 0,r)).then(function(r){return[e,r]})})}catch(e){return Promise.reject(e)}};
+//# sourceMappingURL=basic-dashed-external.js.map
+"
+`;
+
+exports[`fixtures build basic-dashed-external with microbundle 5`] = `
+"!function(e,t){\\"object\\"==typeof exports&&\\"undefined\\"!=typeof module?module.exports=t(require(\\"tiny-glob\\")):\\"function\\"==typeof define&&define.amd?define([\\"tiny-glob\\"],t):(e=e||self).basicDashedExternal=t(e.tinyGlob)}(this,function(e){e=e&&Object.prototype.hasOwnProperty.call(e,\\"default\\")?e.default:e;var t=function(){try{var e=arguments;return Promise.resolve([].slice.call(e).reduce(function(e,t){return e+t},0))}catch(e){return Promise.reject(e)}};return console.log(e),function(){try{var e=arguments,r=[].slice.call(e);return Promise.resolve(t.apply(void 0,r)).then(function(e){return Promise.resolve(t.apply(void 0,r)).then(function(t){return[e,t]})})}catch(e){return Promise.reject(e)}}});
+//# sourceMappingURL=basic-dashed-external.umd.js.map
+"
+`;
+
 exports[`fixtures build basic-flow with microbundle 1`] = `
 "Used script: microbundle
 
diff --git a/test/fixtures/basic-dashed-external/package.json b/test/fixtures/basic-dashed-external/package.json
new file mode 100644
index 00000000..ab591fad
--- /dev/null
+++ b/test/fixtures/basic-dashed-external/package.json
@@ -0,0 +1,9 @@
+{
+  "name": "basic-dashed-external",
+  "scripts": {
+    "build": "microbundle"
+  },
+  "dependencies": {
+    "tiny-glob": "^0.2.6"
+  }
+}
diff --git a/test/fixtures/basic-dashed-external/src/index.js b/test/fixtures/basic-dashed-external/src/index.js
new file mode 100644
index 00000000..f1fd29e2
--- /dev/null
+++ b/test/fixtures/basic-dashed-external/src/index.js
@@ -0,0 +1,8 @@
+import tinyglob from 'tiny-glob';
+console.log(tinyglob);
+
+import { two } from './two';
+
+export default async function(...args) {
+	return [await two(...args), await two(...args)];
+}
diff --git a/test/fixtures/basic-dashed-external/src/two.js b/test/fixtures/basic-dashed-external/src/two.js
new file mode 100644
index 00000000..9f1f741b
--- /dev/null
+++ b/test/fixtures/basic-dashed-external/src/two.js
@@ -0,0 +1,3 @@
+export async function two(...args) {
+	return args.reduce((total, value) => total + value, 0);
+}