diff --git a/lib/rules/no-side-effects-in-computed-properties.js b/lib/rules/no-side-effects-in-computed-properties.js
index 54ededbdb..a0d508014 100644
--- a/lib/rules/no-side-effects-in-computed-properties.js
+++ b/lib/rules/no-side-effects-in-computed-properties.js
@@ -8,6 +8,7 @@ const utils = require('../utils')
 
 /**
  * @typedef {import('../utils').VueObjectData} VueObjectData
+ * @typedef {import('../utils').VueVisitor} VueVisitor
  * @typedef {import('../utils').ComponentComputedProperty} ComponentComputedProperty
  */
 
@@ -32,8 +33,8 @@ module.exports = {
     const computedPropertiesMap = new Map()
     /** @type {Array<FunctionExpression | ArrowFunctionExpression>} */
     const computedCallNodes = []
-    /** @type {Array<FunctionExpression | ArrowFunctionExpression | FunctionDeclaration>} */
-    const setupFunctions = []
+    /** @type {[number, number][]} */
+    const setupRanges = []
 
     /**
      * @typedef {object} ScopeStack
@@ -57,7 +58,114 @@ module.exports = {
       scopeStack = scopeStack && scopeStack.upper
     }
 
-    return Object.assign(
+    const nodeVisitor = {
+      ':function': onFunctionEnter,
+      ':function:exit': onFunctionExit,
+
+      /**
+       * @param {(Identifier | ThisExpression) & {parent: MemberExpression}} node
+       * @param {VueObjectData|undefined} [info]
+       */
+      'MemberExpression > :matches(Identifier, ThisExpression)'(node, info) {
+        if (!scopeStack) {
+          return
+        }
+        const targetBody = scopeStack.body
+
+        const computedProperty = (
+          info ? computedPropertiesMap.get(info.node) || [] : []
+        ).find((cp) => {
+          return (
+            cp.value &&
+            cp.value.range[0] <= node.range[0] &&
+            node.range[1] <= cp.value.range[1] &&
+            targetBody === cp.value
+          )
+        })
+        if (computedProperty) {
+          if (!utils.isThis(node, context)) {
+            return
+          }
+          const mem = node.parent
+          if (mem.object !== node) {
+            return
+          }
+
+          const invalid = utils.findMutating(mem)
+          if (invalid) {
+            context.report({
+              node: invalid.node,
+              message: 'Unexpected side effect in "{{key}}" computed property.',
+              data: { key: computedProperty.key || 'Unknown' }
+            })
+          }
+          return
+        }
+
+        // ignore `this` for computed functions
+        if (node.type === 'ThisExpression') {
+          return
+        }
+
+        const computedFunction = computedCallNodes.find(
+          (c) =>
+            c.range[0] <= node.range[0] &&
+            node.range[1] <= c.range[1] &&
+            targetBody === c.body
+        )
+        if (!computedFunction) {
+          return
+        }
+
+        const mem = node.parent
+        if (mem.object !== node) {
+          return
+        }
+
+        const variable = findVariable(context.getScope(), node)
+        if (!variable || variable.defs.length !== 1) {
+          return
+        }
+
+        const def = variable.defs[0]
+        if (
+          def.type === 'ImplicitGlobalVariable' ||
+          def.type === 'TDZ' ||
+          def.type === 'ImportBinding'
+        ) {
+          return
+        }
+
+        const isDeclaredInsideSetup = setupRanges.some(
+          ([start, end]) =>
+            start <= def.node.range[0] && def.node.range[1] <= end
+        )
+        if (!isDeclaredInsideSetup) {
+          return
+        }
+
+        if (
+          computedFunction.range[0] <= def.node.range[0] &&
+          def.node.range[1] <= computedFunction.range[1]
+        ) {
+          // mutating local variables are accepted
+          return
+        }
+
+        const invalid = utils.findMutating(node)
+        if (invalid) {
+          context.report({
+            node: invalid.node,
+            message: 'Unexpected side effect in computed function.'
+          })
+        }
+      }
+    }
+    const scriptSetupNode = utils.getScriptSetupElement(context)
+    if (scriptSetupNode) {
+      setupRanges.push(scriptSetupNode.range)
+    }
+    return utils.compositingVisitors(
       {
         Program() {
           const tracker = new ReferenceTracker(context.getScope())
@@ -80,120 +188,17 @@ module.exports = {
           }
         }
       },
-      utils.defineVueVisitor(context, {
-        onVueObjectEnter(node) {
-          computedPropertiesMap.set(node, utils.getComputedProperties(node))
-        },
-        ':function': onFunctionEnter,
-        ':function:exit': onFunctionExit,
-        onSetupFunctionEnter(node) {
-          setupFunctions.push(node)
-        },
-
-        /**
-         * @param {(Identifier | ThisExpression) & {parent: MemberExpression}} node
-         * @param {VueObjectData} data
-         */
-        'MemberExpression > :matches(Identifier, ThisExpression)'(
-          node,
-          { node: vueNode }
-        ) {
-          if (!scopeStack) {
-            return
-          }
-          const targetBody = scopeStack.body
-
-          const computedProperty = /** @type {ComponentComputedProperty[]} */ (
-            computedPropertiesMap.get(vueNode)
-          ).find((cp) => {
-            return (
-              cp.value &&
-              node.loc.start.line >= cp.value.loc.start.line &&
-              node.loc.end.line <= cp.value.loc.end.line &&
-              targetBody === cp.value
-            )
+      scriptSetupNode
+        ? utils.defineScriptSetupVisitor(context, nodeVisitor)
+        : utils.defineVueVisitor(context, {
+            onVueObjectEnter(node) {
+              computedPropertiesMap.set(node, utils.getComputedProperties(node))
+            },
+            onSetupFunctionEnter(node) {
+              setupRanges.push(node.body.range)
+            },
+            ...nodeVisitor
           })
-          if (computedProperty) {
-            if (!utils.isThis(node, context)) {
-              return
-            }
-            const mem = node.parent
-            if (mem.object !== node) {
-              return
-            }
-
-            const invalid = utils.findMutating(mem)
-            if (invalid) {
-              context.report({
-                node: invalid.node,
-                message:
-                  'Unexpected side effect in "{{key}}" computed property.',
-                data: { key: computedProperty.key || 'Unknown' }
-              })
-            }
-            return
-          }
-
-          // ignore `this` for computed functions
-          if (node.type === 'ThisExpression') {
-            return
-          }
-
-          const computedFunction = computedCallNodes.find(
-            (c) =>
-              node.loc.start.line >= c.loc.start.line &&
-              node.loc.end.line <= c.loc.end.line &&
-              targetBody === c.body
-          )
-          if (!computedFunction) {
-            return
-          }
-
-          const mem = node.parent
-          if (mem.object !== node) {
-            return
-          }
-
-          const variable = findVariable(context.getScope(), node)
-          if (!variable || variable.defs.length !== 1) {
-            return
-          }
-
-          const def = variable.defs[0]
-          if (
-            def.type === 'ImplicitGlobalVariable' ||
-            def.type === 'TDZ' ||
-            def.type === 'ImportBinding'
-          ) {
-            return
-          }
-
-          const isDeclaredInsideSetup = setupFunctions.some(
-            (setupFn) =>
-              def.node.loc.start.line >= setupFn.loc.start.line &&
-              def.node.loc.end.line <= setupFn.loc.end.line
-          )
-          if (!isDeclaredInsideSetup) {
-            return
-          }
-
-          if (
-            def.node.loc.start.line >= computedFunction.loc.start.line &&
-            def.node.loc.end.line <= computedFunction.loc.end.line
-          ) {
-            // mutating local variables are accepted
-            return
-          }
-
-          const invalid = utils.findMutating(node)
-          if (invalid) {
-            context.report({
-              node: invalid.node,
-              message: 'Unexpected side effect in computed function.'
-            })
-          }
-        }
-      })
     )
   }
 }
diff --git a/lib/utils/index.js b/lib/utils/index.js
index 5ecda2868..0e6bee93a 100644
--- a/lib/utils/index.js
+++ b/lib/utils/index.js
@@ -908,6 +908,12 @@ module.exports = {
    * @param {RuleContext} context The ESLint rule context object.
    */
   isScriptSetup,
+  /**
+   * Gets the element of `<script setup>`
+   * @param {RuleContext} context The ESLint rule context object.
+   * @returns {VElement | null} the element of `<script setup>`
+   */
+  getScriptSetupElement,
 
   /**
    * Check if current file is a Vue instance or component and call callback
diff --git a/tests/lib/rules/no-side-effects-in-computed-properties.js b/tests/lib/rules/no-side-effects-in-computed-properties.js
index 647910d4a..7c4aabe95 100644
--- a/tests/lib/rules/no-side-effects-in-computed-properties.js
+++ b/tests/lib/rules/no-side-effects-in-computed-properties.js
@@ -591,6 +591,141 @@ ruleTester.run('no-side-effects-in-computed-properties', rule, {
           message: 'Unexpected side effect in computed function.'
         }
       ]
+    },
+
+    {
+      filename: 'test.vue',
+      code: `
+      <script setup>
+      import {ref, computed} from 'vue'
+      const foo = useFoo()
+      const asd = { qwe: {} }
+      function a () {}
+      class A {}
+
+      const test1 = computed(() => {
+        foo.firstName = 'lorem'
+        asd.qwe.zxc = 'lorem'
+        return foo.firstName + ' ' + foo.lastName
+      })
+      const test2 = computed(() => {
+        foo.count += 2;
+        foo.count++;
+        return foo.count;
+      })
+      const test3 = computed(() => foo.something.reverse())
+      const test4 = computed(() => {
+        const test = foo.another.something.push('example')
+        return 'something'
+      })
+      const test5 = computed(() => {
+        foo.something[index] = foo.thing[index]
+        return foo.something
+      })
+      const test6 = computed(() => foo.something.keys.sort())
+      const test7 = computed({
+        get() {
+          return foo.something.reverse()
+        }
+      })
+      const test8 = computed(() => {
+        a.name = ''
+      })
+      const test9 = computed(() => {
+        A.name = ''
+      })
+      const test10 = computed(() => (foo.a = '', true))
+
+      const test100 = computed(() => {
+        const a = foo
+        a.count++ // false negative
+      })
+      </script>
+      `,
+      errors: [
+        {
+          line: 10,
+          message: 'Unexpected side effect in computed function.'
+        },
+        {
+          line: 11,
+          message: 'Unexpected side effect in computed function.'
+        },
+        {
+          line: 15,
+          message: 'Unexpected side effect in computed function.'
+        },
+        {
+          line: 16,
+          message: 'Unexpected side effect in computed function.'
+        },
+        {
+          line: 19,
+          message: 'Unexpected side effect in computed function.'
+        },
+        {
+          line: 21,
+          message: 'Unexpected side effect in computed function.'
+        },
+        {
+          line: 25,
+          message: 'Unexpected side effect in computed function.'
+        },
+        {
+          line: 28,
+          message: 'Unexpected side effect in computed function.'
+        },
+        {
+          line: 31,
+          message: 'Unexpected side effect in computed function.'
+        },
+        {
+          line: 35,
+          message: 'Unexpected side effect in computed function.'
+        },
+        {
+          line: 38,
+          message: 'Unexpected side effect in computed function.'
+        },
+        {
+          line: 40,
+          message: 'Unexpected side effect in computed function.'
+        }
+      ]
+    },
+    {
+      filename: 'test.vue',
+      code: `
+      <script setup>
+      import {reactive, computed} from 'vue'
+      const arr = reactive([])
+
+      const test1 = computed(() => arr.reverse())
+      </script>
+      `,
+      errors: [
+        {
+          line: 6,
+          message: 'Unexpected side effect in computed function.'
+        }
+      ]
+    },
+    {
+      filename: 'test.vue',
+      code: `
+      <script lang="ts" setup>
+      import {ref, computed} from 'vue'
+      const foo = useFoo()
+
+      const test1 = computed(() => foo.something.reverse())
+      </script>
+      `,
+      errors: [
+        {
+          line: 6,
+          message: 'Unexpected side effect in computed function.'
+        }
+      ]
     }
   ]
 })