diff --git a/auth.js b/auth.js
index fafea54..80aed9c 100644
--- a/auth.js
+++ b/auth.js
@@ -27,6 +27,21 @@ const hasAuth = (regKey, opts) => (
   opts[`${regKey}:username`] && opts[`${regKey}:_password`]
 )
 
+const sameHost = (a, b) => {
+  const parsedA = new URL(a)
+  const parsedB = new URL(b)
+  return parsedA.host === parsedB.host
+}
+
+const getRegistry = opts => {
+  const { spec } = opts
+  const { scope: specScope, subSpec } = spec ? npa(spec) : {}
+  const subSpecScope = subSpec && subSpec.scope
+  const scope = subSpec ? subSpecScope : specScope
+  const scopeReg = scope && opts[`${scope}:registry`]
+  return scopeReg || opts.registry
+}
+
 const getAuth = (uri, opts = {}) => {
   const { forceAuth } = opts
   if (!uri)
@@ -44,19 +59,19 @@ const getAuth = (uri, opts = {}) => {
     })
   }
 
-  // no auth for this URI
-  if (!regKey && opts.spec) {
-    // If making a tarball request to a different base URI than the
-    // registry where we logged in, but the same auth SHOULD be sent
-    // to that artifact host, then we track where it was coming in from,
-    // and warn the user if we get a 4xx error on it.
-    const { spec } = opts
-    const { scope: specScope, subSpec } = npa(spec)
-    const subSpecScope = subSpec && subSpec.scope
-    const scope = subSpec ? subSpecScope : specScope
-    const scopeReg = scope && opts[`${scope}:registry`]
-    const scopeAuthKey = scopeReg && regKeyFromURI(scopeReg, opts)
-    return new Auth({ scopeAuthKey })
+  // no auth for this URI, but might have it for the registry
+  if (!regKey) {
+    const registry = getRegistry(opts)
+    if (registry && uri !== registry && sameHost(uri, registry))
+      return getAuth(registry, opts)
+    else if (registry !== opts.registry) {
+      // If making a tarball request to a different base URI than the
+      // registry where we logged in, but the same auth SHOULD be sent
+      // to that artifact host, then we track where it was coming in from,
+      // and warn the user if we get a 4xx error on it.
+      const scopeAuthKey = regKeyFromURI(registry, opts)
+      return new Auth({ scopeAuthKey })
+    }
   }
 
   const {
diff --git a/test/auth.js b/test/auth.js
index 87f3f8c..a64394e 100644
--- a/test/auth.js
+++ b/test/auth.js
@@ -428,3 +428,33 @@ t.test('scopeAuthKey tests', t => {
 
   t.end()
 })
+
+t.test('registry host matches, path does not, send auth', t => {
+  const opts = {
+    '@other-scope:registry': 'https://other-scope-registry.com/other/scope/',
+    '//other-scope-registry.com/other/scope/:_authToken': 'cafebad',
+    '@scope:registry': 'https://scope-host.com/scope/host/',
+    '//scope-host.com/scope/host/:_authToken': 'c0ffee',
+    registry: 'https://registry.example.com/some/path/',
+  }
+  const uri = 'https://scope-host.com/blahblah/bloobloo/foo.tgz'
+  t.same(getAuth(uri, { ...opts, spec: '@scope/foo' }), {
+    scopeAuthKey: null,
+    token: 'c0ffee',
+    auth: null,
+    isBasicAuth: false,
+  })
+  t.same(getAuth(uri, { ...opts, spec: '@other-scope/foo' }), {
+    scopeAuthKey: '//other-scope-registry.com/other/scope/',
+    token: null,
+    auth: null,
+    isBasicAuth: false,
+  })
+  t.same(getAuth(uri, { ...opts, registry: 'https://scope-host.com/scope/host/' }), {
+    scopeAuthKey: null,
+    token: 'c0ffee',
+    auth: null,
+    isBasicAuth: false,
+  })
+  t.end()
+})