diff --git a/plugins/dev-scripts/bin/blockly-scripts.js b/plugins/dev-scripts/bin/blockly-scripts.js
index 8bc5db5311..6661d8a145 100755
--- a/plugins/dev-scripts/bin/blockly-scripts.js
+++ b/plugins/dev-scripts/bin/blockly-scripts.js
@@ -20,7 +20,6 @@ const availableScripts = [
   'predeploy',
   'lint',
   'test',
-  'postinstall',
   'auditFix',
 ];
 
diff --git a/plugins/dev-scripts/scripts/postinstall.js b/plugins/dev-scripts/scripts/postinstall.js
deleted file mode 100644
index 9b3ea766b3..0000000000
--- a/plugins/dev-scripts/scripts/postinstall.js
+++ /dev/null
@@ -1,49 +0,0 @@
-/**
- * @license
- * Copyright 2020 Google LLC
- * SPDX-License-Identifier: Apache-2.0
- */
-
-/**
- * @fileoverview A 'postinstall' script for Blockly extension packages.
- * This script:
- *   Completes post install tasks if necessary.
- * @author samelh@google.com (Sam El-Husseini)
- */
-
-'use strict';
-
-const fs = require('fs');
-const path = require('path');
-const execSync = require('child_process').execSync;
-
-const appDirectory = fs.realpathSync(process.cwd());
-const resolveApp = (relativePath) => path.resolve(appDirectory, relativePath);
-
-const packageJson = require(resolveApp('package.json'));
-const blocklyNodeModulesPath = resolveApp('node_modules/blockly');
-
-// Check if we have installed blockly from git instead of npm.
-const blocklyDependency =
-  (packageJson.dependencies && packageJson.dependencies['blockly']) ||
-  (packageJson.devDependencies && packageJson.devDependencies['blockly']);
-
-if (!blocklyDependency) {
-  return;
-}
-
-if (blocklyDependency.indexOf('git://') !== 0) {
-  return;
-}
-
-// Blockly was installed from a Git repo. Install and build.
-console.log(`Running postinstall steps for ${packageJson.name}`);
-
-// Run npm install.
-execSync(`npm install`, {cwd: blocklyNodeModulesPath, stdio: [0, 1, 2]});
-
-// Build.
-execSync(`npm run build`, {cwd: blocklyNodeModulesPath, stdio: [0, 1, 2]});
-
-// Package.
-execSync(`npm run package`, {cwd: blocklyNodeModulesPath, stdio: [0, 1, 2]});
diff --git a/plugins/renderer-inline-row-separators/package.json b/plugins/renderer-inline-row-separators/package.json
index f941ab9eb1..8b082a3a8a 100644
--- a/plugins/renderer-inline-row-separators/package.json
+++ b/plugins/renderer-inline-row-separators/package.json
@@ -8,7 +8,6 @@
     "clean": "blockly-scripts clean",
     "lint": "blockly-scripts lint",
     "predeploy": "blockly-scripts predeploy",
-    "postinstall": "blockly-scripts postinstall",
     "start": "blockly-scripts start",
     "test": "blockly-scripts test"
   },
diff --git a/plugins/shadow-block-converter/package.json b/plugins/shadow-block-converter/package.json
index 3865bb40f0..8391a4aec9 100644
--- a/plugins/shadow-block-converter/package.json
+++ b/plugins/shadow-block-converter/package.json
@@ -8,7 +8,6 @@
     "clean": "blockly-scripts clean",
     "lint": "blockly-scripts lint",
     "predeploy": "blockly-scripts predeploy",
-    "postinstall": "blockly-scripts postinstall",
     "start": "blockly-scripts start",
     "test": "blockly-scripts test"
   },
diff --git a/plugins/strict-connection-checker/package.json b/plugins/strict-connection-checker/package.json
index f4c4015d8c..1f9f8fc266 100644
--- a/plugins/strict-connection-checker/package.json
+++ b/plugins/strict-connection-checker/package.json
@@ -8,7 +8,6 @@
     "clean": "blockly-scripts clean",
     "lint": "blockly-scripts lint",
     "predeploy": "blockly-scripts predeploy",
-    "postinstall": "blockly-scripts postinstall",
     "start": "blockly-scripts start",
     "test": "blockly-scripts test"
   },