diff --git a/lib/compiler.js b/lib/compiler.js
index 70459ab..c6738c7 100644
--- a/lib/compiler.js
+++ b/lib/compiler.js
@@ -81,8 +81,10 @@ module.exports = function compile(options) {
   delete modelsConfig._meta;
 
   var modelSources = options.modelSources || modelsMeta.sources || ['./models'];
+  var modelDefinitions = options.modelDefinitions || undefined;
+
   var modelInstructions = buildAllModelInstructions(
-    modelsRootDir, modelsConfig, modelSources);
+    modelsRootDir, modelsConfig, modelSources, modelDefinitions);
 
   var mixinDirs = options.mixinDirs || [];
   var mixinInstructions = buildAllMixinInstructions(
@@ -192,8 +194,8 @@ function tryReadDir() {
   }
 }
 
-function buildAllModelInstructions(rootDir, modelsConfig, sources) {
-  var registry = findModelDefinitions(rootDir, sources);
+function buildAllModelInstructions(rootDir, modelsConfig, sources, modelDefinitions) {
+  var registry = verifyModelDefinitions(rootDir, modelDefinitions) || findModelDefinitions(rootDir, sources);
 
   var modelNamesToBuild = addAllBaseModels(registry, Object.keys(modelsConfig));
 
@@ -274,6 +276,68 @@ function sortByInheritance(instructions) {
     });
 }
 
+/**
+ * Returns matching files with a supported `sourceFile` extension like `.js` or `.coffee`
+ * @param allFiles {Array}
+ * @param basename {string}
+ * @returns {Array}
+ */
+function filterValidSourceFiles(allFiles, basename) {
+  var base, ext, validFileType;
+  return allFiles
+    .filter(function(f) {
+      ext = path.extname(f);
+      base = path.basename(f, ext);
+      validFileType = (ext !== '.node') && (ext !== '.json') &&
+      ((typeof require.extensions[ext]) === 'function');
+      return validFileType && (base === basename);
+    });
+}
+
+function verifyModelDefinitions(rootDir, modelDefinitions) {
+  if (!modelDefinitions || modelDefinitions.length < 1) {
+    return undefined;
+  }
+
+  var registry = {};
+  modelDefinitions.forEach(function(definition, idx) {
+    if (definition.sourceFile) {
+      try {
+        var fullPath = path.resolve(rootDir, definition.sourceFile);
+        var basename = path.basename(fullPath, path.extname(fullPath));
+        var files = tryReadDir(path.dirname(fullPath));
+        var sourceFile = filterValidSourceFiles(files, basename)[0];
+
+        definition.sourceFile = path.join(path.dirname(fullPath), sourceFile);
+        definition.sourceFile = require.resolve(definition.sourceFile);
+      } catch (err) {
+        debug('Model source code not found: %s - %s',
+          definition.sourceFile,
+          err.code || err);
+        definition.sourceFile = undefined;
+      }
+    } else {
+      definition.sourceFile = undefined;
+    }
+
+    debug('Found model "%s" - %s %s',
+      definition.definition.name,
+      'from options',
+      definition.sourceFile ?
+        path.relative(rootDir, definition.sourceFile) :
+        '(no source file)');
+
+    var modelName = definition.definition.name;
+    if (!modelName) {
+      debug('Skipping model definition without Model name (from options.modelDefinitions @ index %s)', idx);
+      return;
+    }
+    registry[modelName] = definition;
+  });
+
+  return registry;
+}
+
 function findModelDefinitions(rootDir, sources) {
   var registry = {};
 
diff --git a/test/compiler.test.js b/test/compiler.test.js
index 9ed42e3..1eb1469 100644
--- a/test/compiler.test.js
+++ b/test/compiler.test.js
@@ -78,6 +78,193 @@ describe('compiler', function() {
     it('has datasources definition', function() {
       expect(instructions.dataSources).to.eql(options.dataSources);
     });
+
+    describe('with custom model definitions', function() {
+      var dataSources = {
+        'the-db': {
+          connector: 'memory',
+          defaultForType: 'db'
+        }
+      };
+
+      it('should loads model without definition.', function() {
+        var instruction = boot.compile({
+          appRootDir: appdir.PATH,
+          models: {
+            'model-without-definitions': {
+              dataSource: 'the-db'
+            }
+          },
+          modelDefinitions: [],
+          dataSources: dataSources
+        });
+        expect(instruction.models[0].name).to.equal('model-without-definitions');
+        expect(instruction.models[0].definition).to.equal(undefined);
+        expect(instruction.models[0].sourceFile).to.equal(undefined);
+      });
+
+      it('should load coffeescript models', function() {
+        require('coffee-script/register');
+
+        appdir.writeFileSync('custom-models/coffee-model-with-definitions.coffee', '');
+        var instruction = boot.compile({
+          appRootDir: appdir.PATH,
+          models: {
+            'coffee-model-with-definitions': {
+              dataSource: 'the-db'
+            }
+          },
+          modelDefinitions: [
+            {
+              definition: {
+                name: 'coffee-model-with-definitions'
+              },
+              sourceFile: path.join(appdir.PATH, 'custom-models', 'coffee-model-with-definitions.coffee')
+            }
+          ],
+          dataSources: dataSources
+        });
+        expect(instruction.models[0].name).to.equal('coffee-model-with-definitions');
+        expect(instruction.models[0].definition).not.to.equal(undefined);
+        expect(instruction.models[0].sourceFile).not.to.equal(undefined);
+      });
+
+      it('should handle sourceFile path without extension.', function() {
+        require('coffee-script/register');
+
+        appdir.writeFileSync('custom-models/coffee-model-without-ext.coffee', '');
+        appdir.writeFileSync('custom-models/js-model-without-ext.js', '');
+        var instruction = boot.compile({
+          appRootDir: appdir.PATH,
+          models: {
+            'coffee-model-without-ext': {
+              dataSource: 'the-db'
+            },
+            'js-model-without-ext': {
+              dataSource: 'the-db'
+            }
+          },
+          modelDefinitions: [
+            {
+              definition: {
+                name: 'coffee-model-without-ext'
+              },
+              sourceFile: path.join(appdir.PATH, 'custom-models', 'coffee-model-without-ext')
+            },
+            {
+              definition: {
+                name: 'js-model-without-ext'
+              },
+              sourceFile: path.join(appdir.PATH, 'custom-models', 'js-model-without-ext')
+            }
+          ],
+          dataSources: dataSources
+        });
+        expect(instruction.models[0].name).to.equal('coffee-model-without-ext');
+        expect(instruction.models[0].sourceFile)
+          .to.equal(path.join(appdir.PATH, 'custom-models', 'coffee-model-without-ext.coffee'));
+
+        expect(instruction.models[1].name).to.equal('js-model-without-ext');
+        expect(instruction.models[1].sourceFile)
+          .to.equal(path.join(appdir.PATH, 'custom-models', 'js-model-without-ext.js'));
+      });
+
+      it('should set source file path if the file exist.', function() {
+        appdir.writeFileSync('custom-models/model-with-definitions.js', '');
+        var instruction = boot.compile({
+          appRootDir: appdir.PATH,
+          models: {
+            'model-with-definitions': {
+              dataSource: 'the-db'
+            }
+          },
+          modelDefinitions: [
+            {
+              definition: {
+                name: 'model-with-definitions'
+              },
+              sourceFile: path.join(appdir.PATH, 'custom-models', 'model-with-definitions.js')
+            }
+          ],
+          dataSources: dataSources
+        });
+        expect(instruction.models[0].name).to.equal('model-with-definitions');
+        expect(instruction.models[0].definition).not.to.equal(undefined);
+        expect(instruction.models[0].sourceFile)
+          .to.equal(path.join(appdir.PATH, 'custom-models', 'model-with-definitions.js'));
+      });
+
+      it('should not set source file path if the file does not exist.', function() {
+        var instruction = boot.compile({
+          appRootDir: appdir.PATH,
+          models: {
+            'model-with-definitions-with-falsey-source-file': {
+              dataSource: 'the-db'
+            }
+          },
+          modelDefinitions: [
+            {
+              definition: { // sourceFile is a not existing file.
+                name: 'model-with-definitions-with-falsey-source-file'
+              },
+              sourceFile: path.join(appdir.PATH, 'custom-models', 'model-with-definitions-with-falsey-source-file.js')
+            }
+          ],
+          dataSources: dataSources
+        });
+        expect(instruction.models[0].name).to.equal('model-with-definitions-with-falsey-source-file');
+        expect(instruction.models[0].definition).not.to.equal(undefined);
+        expect(instruction.models[0].sourceFile).to.equal(undefined);
+      });
+
+      it('should not set source file path if no source file supplied.', function() {
+        var instruction = boot.compile({
+          appRootDir: appdir.PATH,
+          models: {
+            'model-with-definitions-without-source-file-property': {
+              dataSource: 'the-db'
+            }
+          },
+          modelDefinitions: [
+            {
+              definition: { // sourceFile is a not existing file.
+                name: 'model-with-definitions-without-source-file-property'
+              }
+            }
+          ],
+          dataSources: dataSources
+        });
+        expect(instruction.models[0].name).to.equal('model-with-definitions-without-source-file-property');
+        expect(instruction.models[0].definition).not.to.equal(undefined);
+        expect(instruction.models[0].sourceFile).to.equal(undefined);
+      });
+
+      it('should loads models defined in `models` only.', function() {
+        var instruction = boot.compile({
+          appRootDir: appdir.PATH,
+          models: {
+            'some-model': {
+              dataSource: 'the-db'
+            }
+          },
+          modelDefinitions: [
+            {
+              definition: {
+                name: 'some-model'
+              }
+            },
+            {
+              definition: {
+                name: 'some-fictional-model'
+              }
+            }
+          ],
+          dataSources: dataSources
+        });
+
+        expect(instruction.models).to.have.length(1);
+      });
+    });
   });
 
   describe('from directory', function() {