diff --git a/package.json b/package.json
index 580c5681ef..95c25db87e 100644
--- a/package.json
+++ b/package.json
@@ -59,7 +59,7 @@
     "test-watch": "NODE_ENV=test jest --watchAll",
     "test-ci": "NODE_ENV=test jest --ci --forceExit --reporters=default --reporters=jest-junit",
     "test-coverage": "NODE_ENV=test jest --coverage",
-    "lint": "oxlint --quiet src modules",
+    "lint": "oxlint --quiet src modules && node scripts/check-sentry-browser-version.mjs",
     "lint-native": "swiftlint ./modules && ktlint ./modules",
     "lint-native:fix": "swiftlint --fix ./modules && ktlint --format ./modules",
     "lexicons:generate": "lex build --clear --index-file --import-ext ''",
diff --git a/scripts/check-sentry-browser-version.mjs b/scripts/check-sentry-browser-version.mjs
new file mode 100644
index 0000000000..7b3ed3ed5f
--- /dev/null
+++ b/scripts/check-sentry-browser-version.mjs
@@ -0,0 +1,48 @@
+#!/usr/bin/env node
+/**
+ * Verifies that our direct @sentry/browser dependency is pinned to the exact
+ * version @sentry/react-native depends on.
+ *
+ * The web build initializes @sentry/browser directly (src/logger/sentry/
+ * {lib,setup}/index.web.ts) to keep the RN SDK layer out of the web bundle,
+ * while native still goes through @sentry/react-native, which pins an exact
+ * @sentry/browser version internally. If the two versions drift apart, pnpm
+ * silently installs two copies of the browser SDK - bloating the bundle and
+ * splitting SDK state between them - so when bumping @sentry/react-native,
+ * bump @sentry/browser to the version it pins. This check makes drift loud.
+ *
+ * Usage:  node scripts/check-sentry-browser-version.mjs
+ * Exits 1 on mismatch.
+ */
+
+import {readFileSync} from 'node:fs'
+import {dirname, join, resolve} from 'node:path'
+import {fileURLToPath} from 'node:url'
+
+const root = resolve(dirname(fileURLToPath(import.meta.url)), '..')
+const readPkg = p => JSON.parse(readFileSync(join(root, p), 'utf8'))
+
+const ours = readPkg('package.json').dependencies['@sentry/browser']
+const theirs = readPkg('node_modules/@sentry/react-native/package.json')
+  .dependencies['@sentry/browser']
+
+if (!ours) {
+  console.error(
+    'check-sentry-browser-version: @sentry/browser is missing from ' +
+      'dependencies in package.json. The web Sentry setup imports it directly.',
+  )
+  process.exit(1)
+}
+
+if (ours !== theirs) {
+  console.error(
+    `check-sentry-browser-version: @sentry/browser version mismatch.\n` +
+      `  package.json pins:            ${ours}\n` +
+      `  @sentry/react-native expects: ${theirs}\n` +
+      `Set "@sentry/browser": "${theirs}" in package.json so pnpm resolves a ` +
+      `single copy of the browser SDK.`,
+  )
+  process.exit(1)
+}
+
+console.log(`check-sentry-browser-version: OK (${ours})`)