diff --git a/packages/babel-core/src/config/loading/files/index-browser.js b/packages/babel-core/src/config/loading/files/index-browser.js
index 2c8f80d79f..1d0b249225 100644
--- a/packages/babel-core/src/config/loading/files/index-browser.js
+++ b/packages/babel-core/src/config/loading/files/index-browser.js
@@ -42,21 +42,3 @@ export function loadPreset(
     `Cannot load preset ${name} relative to ${dirname} in a browser`,
   );
 }
-
-export function loadParser(
-  name: string,
-  dirname: string,
-): { filepath: string, value: Function } {
-  throw new Error(
-    `Cannot load parser ${name} relative to ${dirname} in a browser`,
-  );
-}
-
-export function loadGenerator(
-  name: string,
-  dirname: string,
-): { filepath: string, value: Function } {
-  throw new Error(
-    `Cannot load generator ${name} relative to ${dirname} in a browser`,
-  );
-}
diff --git a/packages/babel-core/src/config/loading/files/plugins.js b/packages/babel-core/src/config/loading/files/plugins.js
index eed68a4d31..68b369225d 100644
--- a/packages/babel-core/src/config/loading/files/plugins.js
+++ b/packages/babel-core/src/config/loading/files/plugins.js
@@ -57,62 +57,6 @@ export function loadPreset(
   return { filepath, value };
 }
 
-export function loadParser(
-  name: string,
-  dirname: string,
-): { filepath: string, value: Function } {
-  const filepath = resolve.sync(name, { basedir: dirname });
-
-  const mod = requireModule("parser", filepath);
-
-  if (!mod) {
-    throw new Error(
-      `Parser ${name} relative to ${dirname} does not export an object`,
-    );
-  }
-  if (typeof mod.parse !== "function") {
-    throw new Error(
-      `Parser ${name} relative to ${dirname} does not export a .parse function`,
-    );
-  }
-  const value = mod.parse;
-
-  debug("Loaded parser %o from %o.", name, dirname);
-
-  return {
-    filepath,
-    value,
-  };
-}
-
-export function loadGenerator(
-  name: string,
-  dirname: string,
-): { filepath: string, value: Function } {
-  const filepath = resolve.sync(name, { basedir: dirname });
-
-  const mod = requireModule("generator", filepath);
-
-  if (!mod) {
-    throw new Error(
-      `Generator ${name} relative to ${dirname} does not export an object`,
-    );
-  }
-  if (typeof mod.print !== "function") {
-    throw new Error(
-      `Generator ${name} relative to ${dirname} does not export a .print function`,
-    );
-  }
-  const value = mod.print;
-
-  debug("Loaded generator %o from %o.", name, dirname);
-
-  return {
-    filepath,
-    value,
-  };
-}
-
 function standardizeName(type: "plugin" | "preset", name: string) {
   // Let absolute and relative paths through.
   if (path.isAbsolute(name)) return name;
diff --git a/packages/babel-core/src/config/option-manager.js b/packages/babel-core/src/config/option-manager.js
index 20cab68f1c..6162b47df9 100644
--- a/packages/babel-core/src/config/option-manager.js
+++ b/packages/babel-core/src/config/option-manager.js
@@ -12,12 +12,7 @@ import { makeWeakCache } from "./caching";
 import { getEnv } from "./helpers/environment";
 import { validate, type ValidatedOptions, type PluginItem } from "./options";
 
-import {
-  loadPlugin,
-  loadPreset,
-  loadParser,
-  loadGenerator,
-} from "./loading/files";
+import { loadPlugin, loadPreset } from "./loading/files";
 
 type MergeOptions =
   | ConfigItem
@@ -196,7 +191,7 @@ const loadConfig = makeWeakCache((config: MergeOptions): {
   plugins: Array<BasicDescriptor>,
   presets: Array<BasicDescriptor>,
 } => {
-  const options = normalizeOptions(config);
+  const options = config.options;
 
   const plugins = (config.options.plugins || []).map((plugin, index) =>
     createDescriptor(plugin, loadPlugin, config.dirname, {
@@ -321,35 +316,6 @@ const instantiatePreset = makeWeakCache(
   },
 );
 
-/**
- * Validate and return the options object for the config.
- */
-function normalizeOptions(config) {
-  //
-  const options = Object.assign({}, config.options);
-
-  if (options.parserOpts && typeof options.parserOpts.parser === "string") {
-    options.parserOpts = Object.assign({}, options.parserOpts);
-    (options.parserOpts: any).parser = loadParser(
-      options.parserOpts.parser,
-      config.dirname,
-    ).value;
-  }
-
-  if (
-    options.generatorOpts &&
-    typeof options.generatorOpts.generator === "string"
-  ) {
-    options.generatorOpts = Object.assign({}, options.generatorOpts);
-    (options.generatorOpts: any).generator = loadGenerator(
-      options.generatorOpts.generator,
-      config.dirname,
-    ).value;
-  }
-
-  return options;
-}
-
 /**
  * Given a plugin/preset item, resolve it into a standard format.
  */
diff --git a/packages/babel-core/src/config/plugin.js b/packages/babel-core/src/config/plugin.js
index edc251d0ce..97b1364777 100644
--- a/packages/babel-core/src/config/plugin.js
+++ b/packages/babel-core/src/config/plugin.js
@@ -8,6 +8,9 @@ import {
   type Validator,
 } from "./option-assertions";
 
+// Note: The casts here are just meant to be static assertions to make sure
+// that the assertion functions actually assert that the value's type matches
+// the declared types.
 const VALIDATORS: ValidatorSet = {
   name: (assertString: Validator<$PropertyType<PluginObject, "name">>),
   manipulateOptions: (assertFunction: Validator<
@@ -21,6 +24,13 @@ const VALIDATORS: ValidatorSet = {
   visitor: (assertVisitorMap: Validator<
     $PropertyType<PluginObject, "visitor">,
   >),
+
+  parserOverride: (assertFunction: Validator<
+    $PropertyType<PluginObject, "parserOverride">,
+  >),
+  generatorOverride: (assertFunction: Validator<
+    $PropertyType<PluginObject, "generatorOverride">,
+  >),
 };
 
 function assertVisitorMap(key: string, value: mixed): VisitorMap {
@@ -70,6 +80,9 @@ export type PluginObject = {
 
   inherits?: Function,
   visitor?: VisitorMap,
+
+  parserOverride?: Function,
+  generatorOverride?: Function,
 };
 
 export function validatePluginObject(obj: {}): PluginObject {
@@ -90,6 +103,9 @@ export default class Plugin {
   pre: Function | void;
   visitor: {};
 
+  parserOverride: Function | void;
+  generatorOverride: Function | void;
+
   options: {};
 
   constructor(plugin: PluginObject, options: {}, key?: string) {
@@ -99,6 +115,9 @@ export default class Plugin {
     this.post = plugin.post;
     this.pre = plugin.pre;
     this.visitor = plugin.visitor || {};
+    this.parserOverride = plugin.parserOverride;
+    this.generatorOverride = plugin.generatorOverride;
+
     this.options = options;
   }
 }
diff --git a/packages/babel-core/src/transformation/file/generate.js b/packages/babel-core/src/transformation/file/generate.js
index e31c1726a1..ac8a1e5de7 100644
--- a/packages/babel-core/src/transformation/file/generate.js
+++ b/packages/babel-core/src/transformation/file/generate.js
@@ -1,5 +1,6 @@
 // @flow
 
+import type { PluginPasses } from "../../config";
 import convertSourceMap, { type SourceMap } from "convert-source-map";
 import sourceMap from "source-map";
 import generate from "@babel/generator";
@@ -7,6 +8,7 @@ import generate from "@babel/generator";
 import type File from "./file";
 
 export default function generateCode(
+  pluginPasses: PluginPasses,
   file: File,
 ): {
   outputCode: string,
@@ -14,12 +16,33 @@ export default function generateCode(
 } {
   const { opts, ast, shebang, code, inputMap } = file;
 
-  let gen = generate;
-  if (opts.generatorOpts && opts.generatorOpts.generator) {
-    gen = opts.generatorOpts.generator;
+  const results = [];
+  for (const plugins of pluginPasses) {
+    for (const plugin of plugins) {
+      const { generatorOverride } = plugin;
+      if (generatorOverride) {
+        const result = generatorOverride(
+          ast,
+          opts.generatorOpts,
+          code,
+          generate,
+        );
+
+        if (result !== undefined) results.push(result);
+      }
+    }
   }
 
-  let { code: outputCode, map: outputMap } = gen(ast, opts.generatorOpts, code);
+  let result;
+  if (results.length === 0) {
+    result = generate(ast, opts.generatorOpts, code);
+  } else if (results.length === 1) {
+    result = results[0];
+  } else {
+    throw new Error("More than one plugin attempted to override codegen.");
+  }
+
+  let { code: outputCode, map: outputMap } = result;
 
   if (shebang) {
     // add back shebang
diff --git a/packages/babel-core/src/transformation/index.js b/packages/babel-core/src/transformation/index.js
index e72eff1804..ecb2a30b12 100644
--- a/packages/babel-core/src/transformation/index.js
+++ b/packages/babel-core/src/transformation/index.js
@@ -10,7 +10,7 @@ import normalizeOptions from "./normalize-opts";
 import normalizeFile from "./normalize-file";
 
 import generateCode from "./file/generate";
-import File from "./file/file";
+import type File from "./file/file";
 
 export type FileResultCallback = {
   (Error, null): any,
@@ -48,19 +48,24 @@ export function runSync(
   code: string,
   ast: ?(BabelNodeFile | BabelNodeProgram),
 ): FileResult {
-  const options = normalizeOptions(config);
-  const input = normalizeFile(options, code, ast);
-
-  const file = new File(options, input);
+  const file = normalizeFile(
+    config.passes,
+    normalizeOptions(config),
+    code,
+    ast,
+  );
 
   transformFile(file, config.passes);
 
-  const { outputCode, outputMap } = options.code ? generateCode(file) : {};
+  const opts = file.opts;
+  const { outputCode, outputMap } = opts.code
+    ? generateCode(config.passes, file)
+    : {};
 
   return {
     metadata: file.metadata,
-    options: options,
-    ast: options.ast ? file.ast : null,
+    options: opts,
+    ast: opts.ast ? file.ast : null,
     code: outputCode === undefined ? null : outputCode,
     map: outputMap === undefined ? null : outputMap,
   };
diff --git a/packages/babel-core/src/transformation/normalize-file.js b/packages/babel-core/src/transformation/normalize-file.js
index f264c4eb1f..2b10c05c9e 100644
--- a/packages/babel-core/src/transformation/normalize-file.js
+++ b/packages/babel-core/src/transformation/normalize-file.js
@@ -1,9 +1,11 @@
 // @flow
 
 import * as t from "@babel/types";
+import type { PluginPasses } from "../config";
 import convertSourceMap, { typeof Converter } from "convert-source-map";
 import { parse } from "babylon";
 import { codeFrameColumns } from "@babel/code-frame";
+import File from "./file/file";
 
 const shebangRegex = /^#!.*/;
 
@@ -15,10 +17,11 @@ export type NormalizedFile = {
 };
 
 export default function normalizeFile(
+  pluginPasses: PluginPasses,
   options: Object,
   code: string,
   ast: ?(BabelNodeFile | BabelNodeProgram),
-): NormalizedFile {
+): File {
   code = `${code || ""}`;
 
   let shebang = null;
@@ -45,35 +48,37 @@ export default function normalizeFile(
       throw new Error("AST root must be a Program or File node");
     }
   } else {
-    ast = parser(options, code);
+    ast = parser(pluginPasses, options, code);
   }
 
-  return {
+  return new File(options, {
     code,
     ast,
     shebang,
     inputMap,
-  };
+  });
 }
 
-function parser(options, code) {
-  let parseCode = parse;
-
-  let { parserOpts } = options;
-  if (parserOpts.parser) {
-    parseCode = parserOpts.parser;
-
-    parserOpts = Object.assign({}, parserOpts, {
-      parser: {
-        parse(source) {
-          return parse(source, parserOpts);
-        },
-      },
-    });
-  }
-
+function parser(pluginPasses, options, code) {
   try {
-    return parseCode(code, parserOpts);
+    const results = [];
+    for (const plugins of pluginPasses) {
+      for (const plugin of plugins) {
+        const { parserOverride } = plugin;
+        if (parserOverride) {
+          const ast = parserOverride(code, options.parserOpts, parse);
+
+          if (ast !== undefined) results.push(ast);
+        }
+      }
+    }
+
+    if (results.length === 0) {
+      return parse(code, options.parserOpts);
+    } else if (results.length === 1) {
+      return results[0];
+    }
+    throw new Error("More than one plugin attempted to override parsing.");
   } catch (err) {
     const loc = err.loc;
     if (loc) {