diff --git a/__fixtures__/arbitraryVariants/arbitraryVariants.js b/__fixtures__/arbitraryVariants/arbitraryVariants.js
new file mode 100644
index 00000000..6f636efd
--- /dev/null
+++ b/__fixtures__/arbitraryVariants/arbitraryVariants.js
@@ -0,0 +1,18 @@
+import tw from './macro'
+
+tw`[section]:hover:block`
+
+tw`[p]:hover:block`
+tw`hover:[p]:block`
+
+tw`[* + *]:block` // Spaces
+tw`[.class1 .class2]:block` // Classes
+
+tw`[.class1]:[.class2]:block` // Multiple dynamic variants
+tw`[.class1 .class2]:[.class3]:block` // Multiple dynamic variants
+
+tw`[p]:placeholder-red-500/[var(--myvar)]`
+tw`[p]:mt-[var(--myvar)]`
+tw`[p]:marginTop[var(--myvar)]`
+
+tw`[p]:(mt-4 mb-4)`
diff --git a/__snapshots__/plugin.test.js.snap b/__snapshots__/plugin.test.js.snap
index fb085d6a..be9cb0d1 100644
--- a/__snapshots__/plugin.test.js.snap
+++ b/__snapshots__/plugin.test.js.snap
@@ -3111,6 +3111,105 @@ tw\`md:text-[red]\`
 })
 
 
+`;
+
+exports[`twin.macro arbitraryVariants.js: arbitraryVariants.js 1`] = `
+
+import tw from './macro'
+
+tw\`[section]:hover:block\`
+
+tw\`[p]:hover:block\`
+tw\`hover:[p]:block\`
+
+tw\`[* + *]:block\` // Spaces
+tw\`[.class1 .class2]:block\` // Classes
+
+tw\`[.class1]:[.class2]:block\` // Multiple dynamic variants
+tw\`[.class1 .class2]:[.class3]:block\` // Multiple dynamic variants
+
+tw\`[p]:placeholder-red-500/[var(--myvar)]\`
+tw\`[p]:mt-[var(--myvar)]\`
+tw\`[p]:marginTop[var(--myvar)]\`
+
+tw\`[p]:(mt-4 mb-4)\`
+
+      ↓ ↓ ↓ ↓ ↓ ↓
+
+;({
+  section: {
+    ':hover': {
+      display: 'block',
+    },
+  },
+})
+;({
+  p: {
+    ':hover': {
+      display: 'block',
+    },
+  },
+})
+;({
+  ':hover': {
+    p: {
+      display: 'block',
+    },
+  },
+})
+;({
+  '* + *': {
+    display: 'block',
+  },
+}) // Spaces
+
+;({
+  '.class1 .class2': {
+    display: 'block',
+  },
+}) // Classes
+
+;({
+  '.class1': {
+    '.class2': {
+      display: 'block',
+    },
+  },
+}) // Multiple dynamic variants
+
+;({
+  '.class1 .class2': {
+    '.class3': {
+      display: 'block',
+    },
+  },
+}) // Multiple dynamic variants
+
+;({
+  p: {
+    '::placeholder': {
+      color: 'rgba(239, 68, 68, var(--myvar))',
+    },
+  },
+})
+;({
+  p: {
+    marginTop: 'var(--myvar)',
+  },
+})
+;({
+  p: {
+    marginTop: 'var(--myvar)',
+  },
+})
+;({
+  p: {
+    marginTop: '1rem',
+    marginBottom: '1rem',
+  },
+})
+
+
 `;
 
 exports[`twin.macro autoCssProp.js: autoCssProp.js 1`] = `
diff --git a/src/variants.js b/src/variants.js
index 6431ad92..a844b30d 100644
--- a/src/variants.js
+++ b/src/variants.js
@@ -39,6 +39,12 @@ const validateVariants = ({ variants, state, ...rest }) => {
       if (isResponsive) return stringifyScreen(state.config, variant)
 
       let foundVariant = fullVariantConfig[variant]
+
+      if (!foundVariant) {
+        const arbitraryVariant = variant.match(/^\[(.+)]/)
+        if (arbitraryVariant) foundVariant = arbitraryVariant[1]
+      }
+
       if (!foundVariant) {
         if (variant === 'only-child') {
           throw new MacroError(
@@ -87,10 +93,14 @@ const splitVariants = ({ classNameRaw, state }) => {
   let variant
   let className = classNameRaw
   while (variant !== null) {
-    variant = className.match(/^([\d_a-z-]+):/)
+    // Match arbitrary variants
+    variant = className.match(/^([\d_a-z-]+):|^\[.*?]:/)
+
     if (variant) {
       className = className.slice(variant[0].length)
-      variantsList.push(variant[1])
+      variantsList.push(
+        variant[0].slice(0, -1).replace(new RegExp(SPACE_ID, 'g'), ' ')
+      )
     }
   }
 
@@ -214,7 +224,8 @@ function spreadVariantGroups(
   const results = []
   classes = classes.slice(start, end).trim()
 
-  const reg = /([\w-]+:)|([\w-./[\]]+!?)|\(|(\S+)/g
+  // variant / class / group
+  const reg = /(\[.*?]:|[\w-]+:)|([\w-./[\]]+!?)|\(|(\S+)/g
 
   let match
   const baseContext = context
@@ -223,7 +234,9 @@ function spreadVariantGroups(
     const [, variant, className, weird] = match
 
     if (variant) {
-      context += variant
+      // Replace arbitrary variant spaces with a placeholder to avoid incorrect splitting
+      const spaceReplacedVariant = variant.replace(/\s+/g, SPACE_ID)
+      context += spaceReplacedVariant
 
       // Skip empty classes
       if (/\s/.test(classes[reg.lastIndex])) {