diff --git a/packages/-ember-data/package.json b/packages/-ember-data/package.json
index 8fbe38295cb..778fc56d413 100644
--- a/packages/-ember-data/package.json
+++ b/packages/-ember-data/package.json
@@ -50,6 +50,7 @@
     "broccoli-string-replace": "^0.1.2",
     "broccoli-test-helper": "^2.0.0",
     "broccoli-uglify-sourcemap": "^3.0.0",
+    "ember-compatibility-helpers": "^1.2.0",
     "ember-cli": "^3.12.0",
     "ember-cli-app-version": "^3.2.0",
     "ember-cli-dependency-checker": "^3.2.0",
diff --git a/packages/-ember-data/tests/unit/model-test.js b/packages/-ember-data/tests/unit/model-test.js
index ebfc7ee9600..c38a1aaa8b9 100644
--- a/packages/-ember-data/tests/unit/model-test.js
+++ b/packages/-ember-data/tests/unit/model-test.js
@@ -14,6 +14,7 @@ import JSONSerializer from '@ember-data/serializer/json';
 import { attr as DSattr } from '@ember-data/model';
 import { recordDataFor } from 'ember-data/-private';
 import { attr, hasMany, belongsTo } from '@ember-data/model';
+import { gte } from 'ember-compatibility-helpers';
 
 module('unit/model - Model', function(hooks) {
   setupTest(hooks);
@@ -1442,6 +1443,42 @@ module('unit/model - Model', function(hooks) {
 
       await cat.save();
     });
+
+    if (gte('3.10.0')) {
+      test('@attr decorator works without parens', async function(assert) {
+        assert.expect(1);
+        let cat;
+
+        class Mascot extends Model {
+          @attr name;
+        }
+
+        this.owner.register('model:mascot', Mascot);
+        adapter.updateRecord = function() {
+          assert.deepEqual(cat.changedAttributes(), {
+            name: ['Argon', 'Helia'],
+          });
+
+          return { data: { id: '1', type: 'mascot' } };
+        };
+
+        cat = store.push({
+          data: {
+            type: 'mascot',
+            id: '1',
+            attributes: {
+              name: 'Argon',
+            },
+          },
+        });
+
+        cat.setProperties({
+          name: 'Helia',
+        });
+
+        await cat.save();
+      });
+    }
   });
 
   module('Misc', function() {
diff --git a/packages/-ember-data/tests/unit/model/relationships-test.js b/packages/-ember-data/tests/unit/model/relationships-test.js
index 62496064ac1..860c1f18d03 100644
--- a/packages/-ember-data/tests/unit/model/relationships-test.js
+++ b/packages/-ember-data/tests/unit/model/relationships-test.js
@@ -3,6 +3,7 @@ import { module, test } from 'qunit';
 import Model from '@ember-data/model';
 import { hasMany, belongsTo } from '@ember-data/model';
 import { get } from '@ember/object';
+import { gte } from 'ember-compatibility-helpers';
 
 class Person extends Model {
   @hasMany('occupation', { async: false }) occupations;
@@ -125,4 +126,35 @@ module('[@ember-data/model] unit - relationships', function(hooks) {
 
     assert.equal(relationship.meta.name, 'streamItems', 'relationship name has not been changed');
   });
+
+  if (gte('3.10.0')) {
+    test('decorators works without parens', function(assert) {
+      let store;
+      let { owner } = this;
+
+      class StreamItem extends Model {
+        @belongsTo user;
+      }
+
+      class User extends Model {
+        @hasMany streamItems;
+      }
+
+      owner.unregister('model:user');
+      owner.register('model:stream-item', StreamItem);
+      owner.register('model:user', User);
+
+      store = owner.lookup('service:store');
+
+      let user = store.modelFor('user');
+
+      const relationships = get(user, 'relationships');
+
+      assert.ok(relationships.has('stream-item'), 'relationship key has been normalized');
+
+      const relationship = relationships.get('stream-item')[0];
+
+      assert.equal(relationship.meta.name, 'streamItems', 'relationship name has not been changed');
+    });
+  }
 });
diff --git a/packages/model/addon/-private/attr.js b/packages/model/addon/-private/attr.js
index 3598d0a165c..0330f2b49a2 100644
--- a/packages/model/addon/-private/attr.js
+++ b/packages/model/addon/-private/attr.js
@@ -3,6 +3,7 @@ import { assert } from '@ember/debug';
 import { DEBUG } from '@glimmer/env';
 import { recordDataFor } from '@ember-data/store/-private';
 import { RECORD_DATA_ERRORS } from '@ember-data/canary-features';
+import { computedMacroWithOptionalParams } from './util';
 
 /**
   @module @ember-data/model
@@ -107,7 +108,7 @@ function hasValue(internalModel, key) {
   @param {Object} options a hash of options
   @return {Attribute}
 */
-export default function attr(type, options) {
+function attr(type, options) {
   if (typeof type === 'object') {
     options = type;
     type = undefined;
@@ -160,3 +161,5 @@ export default function attr(type, options) {
     },
   }).meta(meta);
 }
+
+export default computedMacroWithOptionalParams(attr);
diff --git a/packages/model/addon/-private/belongs-to.js b/packages/model/addon/-private/belongs-to.js
index 24b965a0f86..f696031626d 100644
--- a/packages/model/addon/-private/belongs-to.js
+++ b/packages/model/addon/-private/belongs-to.js
@@ -2,6 +2,7 @@ import { computed } from '@ember/object';
 import { assert, warn, inspect } from '@ember/debug';
 import { normalizeModelName } from '@ember-data/store';
 import { DEBUG } from '@glimmer/env';
+import { computedMacroWithOptionalParams } from './util';
 
 /**
   @module @ember-data/model
@@ -103,7 +104,7 @@ import { DEBUG } from '@glimmer/env';
   @param {Object} options (optional) a hash of options
   @return {Ember.computed} relationship
 */
-export default function belongsTo(modelName, options) {
+function belongsTo(modelName, options) {
   let opts, userEnteredModelName;
   if (typeof modelName === 'object') {
     opts = modelName;
@@ -180,3 +181,5 @@ export default function belongsTo(modelName, options) {
     },
   }).meta(meta);
 }
+
+export default computedMacroWithOptionalParams(belongsTo);
diff --git a/packages/model/addon/-private/has-many.js b/packages/model/addon/-private/has-many.js
index 9d7439b2ba2..671eec0b742 100644
--- a/packages/model/addon/-private/has-many.js
+++ b/packages/model/addon/-private/has-many.js
@@ -5,6 +5,7 @@ import { computed } from '@ember/object';
 import { assert, inspect } from '@ember/debug';
 import { normalizeModelName } from '@ember-data/store';
 import { DEBUG } from '@glimmer/env';
+import { computedMacroWithOptionalParams } from './util';
 
 /**
   `hasMany` is used to define One-To-Many and Many-To-Many
@@ -141,7 +142,7 @@ import { DEBUG } from '@glimmer/env';
   @param {Object} options (optional) a hash of options
   @return {Ember.computed} relationship
 */
-export default function hasMany(type, options) {
+function hasMany(type, options) {
   if (typeof type === 'object') {
     options = type;
     type = undefined;
@@ -199,3 +200,5 @@ export default function hasMany(type, options) {
     },
   }).meta(meta);
 }
+
+export default computedMacroWithOptionalParams(hasMany);
diff --git a/packages/model/addon/-private/util.ts b/packages/model/addon/-private/util.ts
new file mode 100644
index 00000000000..d6cc8f1a512
--- /dev/null
+++ b/packages/model/addon/-private/util.ts
@@ -0,0 +1,31 @@
+import { gte } from 'ember-compatibility-helpers';
+
+export type DecoratorPropertyDescriptor = PropertyDescriptor & { initializer?: any } | undefined;
+
+export function isElementDescriptor(args: any[]): args is [object, string, DecoratorPropertyDescriptor] {
+  let [maybeTarget, maybeKey, maybeDesc] = args;
+
+  return (
+    // Ensure we have the right number of args
+    args.length === 3 &&
+    // Make sure the target is a class or object (prototype)
+    (typeof maybeTarget === 'function' || (typeof maybeTarget === 'object' && maybeTarget !== null)) &&
+    // Make sure the key is a string
+    typeof maybeKey === 'string' &&
+    // Make sure the descriptor is the right shape
+    ((typeof maybeDesc === 'object' &&
+      maybeDesc !== null &&
+      'enumerable' in maybeDesc &&
+      'configurable' in maybeDesc) ||
+      // TS compatibility
+      maybeDesc === undefined)
+  );
+}
+
+export function computedMacroWithOptionalParams(fn) {
+  if (gte('3.10.0')) {
+    return (...maybeDesc: any[]) => (isElementDescriptor(maybeDesc) ? fn()(...maybeDesc) : fn(...maybeDesc));
+  } else {
+    return fn;
+  }
+}
diff --git a/packages/model/package.json b/packages/model/package.json
index e441ceb0a01..6fe5820fae4 100644
--- a/packages/model/package.json
+++ b/packages/model/package.json
@@ -24,6 +24,7 @@
     "@ember-data/-build-infra": "3.14.0-alpha.1",
     "@ember-data/canary-features": "3.14.0-alpha.1",
     "@ember-data/store": "3.14.0-alpha.1",
+    "ember-compatibility-helpers": "^1.2.0",
     "ember-cli-babel": "^7.10.0",
     "ember-cli-string-utils": "^1.1.0",
     "ember-cli-test-info": "^1.0.0",