diff --git a/lib/utils/flat-options.js b/lib/utils/flat-options.js
index 9b83de8c449fa..71edca0718c78 100644
--- a/lib/utils/flat-options.js
+++ b/lib/utils/flat-options.js
@@ -27,6 +27,13 @@ const buildOmitList = obj => {
     omit.add('optional')
 
   obj.omit = [...omit]
+
+  // it would perhaps make more sense to put this in @npmcli/config, but
+  // since we can set dev to be omitted in multiple various legacy ways,
+  // it's better to set it here once it's all resolved.
+  if (obj.omit.includes('dev'))
+    process.env.NODE_ENV = 'production'
+
   return [...omit]
 }
 
diff --git a/test/lib/utils/flat-options.js b/test/lib/utils/flat-options.js
index 3cbf06a48b9ff..ee7620fa784db 100644
--- a/test/lib/utils/flat-options.js
+++ b/test/lib/utils/flat-options.js
@@ -1,6 +1,7 @@
 const t = require('tap')
 
 process.env.NODE = '/path/to/some/node'
+process.env.NODE_ENV = 'development'
 
 const logs = []
 const log = require('npmlog')
@@ -195,43 +196,56 @@ t.test('tag emits warning', t => {
 
 t.test('omit/include options', t => {
   t.test('omit explicitly', t => {
+    const { NODE_ENV } = process.env
     const npm = new Mocknpm({
       omit: ['dev', 'optional', 'peer'],
     })
     t.strictSame(flatOptions(npm).omit, ['dev', 'optional', 'peer'])
+    t.equal(process.env.NODE_ENV, 'production')
+    process.env.NODE_ENV = NODE_ENV
     t.end()
   })
 
   t.test('omit and include some', t => {
+    const { NODE_ENV } = process.env
     const npm = new Mocknpm({
       omit: ['dev', 'optional', 'peer'],
       include: ['peer'],
     })
     t.strictSame(flatOptions(npm).omit, ['dev', 'optional'])
+    t.equal(process.env.NODE_ENV, 'production')
+    process.env.NODE_ENV = NODE_ENV
     t.end()
   })
 
   t.test('dev flag', t => {
+    const { NODE_ENV } = process.env
     const npm = new Mocknpm({
       omit: ['dev', 'optional', 'peer'],
       include: [],
       dev: true,
     })
     t.strictSame(flatOptions(npm).omit, ['optional', 'peer'])
+    t.equal(process.env.NODE_ENV, NODE_ENV)
+    process.env.NODE_ENV = NODE_ENV
     t.end()
   })
 
   t.test('production flag', t => {
+    const { NODE_ENV } = process.env
     const npm = new Mocknpm({
       omit: [],
       include: [],
       production: true,
     })
     t.strictSame(flatOptions(npm).omit, ['dev'])
+    t.equal(process.env.NODE_ENV, 'production')
+    process.env.NODE_ENV = NODE_ENV
     t.end()
   })
 
   t.test('only', t => {
+    const { NODE_ENV } = process.env
     const cases = ['prod', 'production']
     t.plan(cases.length)
     cases.forEach(c => t.test(c, t => {
@@ -241,26 +255,34 @@ t.test('omit/include options', t => {
         only: c,
       })
       t.strictSame(flatOptions(npm).omit, ['dev'])
+      t.equal(process.env.NODE_ENV, 'production')
+      process.env.NODE_ENV = NODE_ENV
       t.end()
     }))
   })
 
   t.test('also dev', t => {
+    const { NODE_ENV } = process.env
     const npm = new Mocknpm({
       omit: ['dev', 'optional', 'peer'],
       also: 'dev',
     })
     t.strictSame(flatOptions(npm).omit, ['optional', 'peer'])
+    t.equal(process.env.NODE_ENV, NODE_ENV)
+    process.env.NODE_ENV = NODE_ENV
     t.end()
   })
 
   t.test('no-optional', t => {
+    const { NODE_ENV } = process.env
     const npm = new Mocknpm({
       optional: false,
       omit: null,
       include: null,
     })
     t.strictSame(flatOptions(npm).omit, ['optional'])
+    t.equal(process.env.NODE_ENV, NODE_ENV)
+    process.env.NODE_ENV = NODE_ENV
     t.end()
   })