diff --git a/lib/rules/one-var.js b/lib/rules/one-var.js
index b370c6d5e19..e3df8320f8b 100644
--- a/lib/rules/one-var.js
+++ b/lib/rules/one-var.js
@@ -5,6 +5,25 @@
 
 "use strict";
 
+//------------------------------------------------------------------------------
+// Requirements
+//------------------------------------------------------------------------------
+
+const astUtils = require("./utils/ast-utils");
+
+//------------------------------------------------------------------------------
+// Helpers
+//------------------------------------------------------------------------------
+
+/**
+ * Determines whether the given node is in a statement list.
+ * @param {ASTNode} node node to check
+ * @returns {boolean} `true` if the given node is in a statement list
+ */
+function isInStatementList(node) {
+    return astUtils.STATEMENT_LIST_PARENTS.has(node.parent.type);
+}
+
 //------------------------------------------------------------------------------
 // Rule Definition
 //------------------------------------------------------------------------------
@@ -268,8 +287,8 @@ module.exports = {
 
         /**
          * Fixer to join VariableDeclaration's into a single declaration
-         * @param   {VariableDeclarator[]} declarations The `VariableDeclaration` to join
-         * @returns {Function}                         The fixer function
+         * @param {VariableDeclarator[]} declarations The `VariableDeclaration` to join
+         * @returns {Function} The fixer function
          */
         function joinDeclarations(declarations) {
             const declaration = declarations[0];
@@ -297,10 +316,17 @@ module.exports = {
 
         /**
          * Fixer to split a VariableDeclaration into individual declarations
-         * @param   {VariableDeclaration}   declaration The `VariableDeclaration` to split
-         * @returns {Function}                          The fixer function
+         * @param {VariableDeclaration} declaration The `VariableDeclaration` to split
+         * @returns {Function|null} The fixer function
          */
         function splitDeclarations(declaration) {
+            const { parent } = declaration;
+
+            // don't autofix code such as: if (foo) var x, y;
+            if (!isInStatementList(parent.type === "ExportNamedDeclaration" ? parent : declaration)) {
+                return null;
+            }
+
             return fixer => declaration.declarations.map(declarator => {
                 const tokenAfterDeclarator = sourceCode.getTokenAfter(declarator);
 
diff --git a/tests/lib/rules/one-var.js b/tests/lib/rules/one-var.js
index 026862e10a7..3388c9d6489 100644
--- a/tests/lib/rules/one-var.js
+++ b/tests/lib/rules/one-var.js
@@ -492,6 +492,16 @@ ruleTester.run("one-var", rule, {
         }
     ],
     invalid: [
+        {
+            code: "var bar = true, baz = false;",
+            output: "var bar = true; var baz = false;",
+            options: ["never"],
+            errors: [{
+                messageId: "split",
+                data: { type: "var" },
+                type: "VariableDeclaration"
+            }]
+        },
         {
             code: "function foo() { var bar = true, baz = false; }",
             output: "function foo() { var bar = true; var baz = false; }",
@@ -502,6 +512,36 @@ ruleTester.run("one-var", rule, {
                 type: "VariableDeclaration"
             }]
         },
+        {
+            code: "if (foo) { var bar = true, baz = false; }",
+            output: "if (foo) { var bar = true; var baz = false; }",
+            options: ["never"],
+            errors: [{
+                messageId: "split",
+                data: { type: "var" },
+                type: "VariableDeclaration"
+            }]
+        },
+        {
+            code: "switch (foo) { case bar: var baz = true, quux = false; }",
+            output: "switch (foo) { case bar: var baz = true; var quux = false; }",
+            options: ["never"],
+            errors: [{
+                messageId: "split",
+                data: { type: "var" },
+                type: "VariableDeclaration"
+            }]
+        },
+        {
+            code: "switch (foo) { default: var baz = true, quux = false; }",
+            output: "switch (foo) { default: var baz = true; var quux = false; }",
+            options: ["never"],
+            errors: [{
+                messageId: "split",
+                data: { type: "var" },
+                type: "VariableDeclaration"
+            }]
+        },
         {
             code: "function foo() { var bar = true; var baz = false; }",
             output: "function foo() { var bar = true,  baz = false; }",
@@ -1942,6 +1982,138 @@ ruleTester.run("one-var", rule, {
                 data: { type: "const" },
                 type: "VariableDeclaration"
             }]
+        },
+
+        // "never" should not autofix declarations in a block position
+        {
+            code: "if (foo) var x, y;",
+            output: null,
+            options: ["never"],
+            errors: [{
+                messageId: "split",
+                data: { type: "var" },
+                type: "VariableDeclaration"
+            }]
+        },
+        {
+            code: "if (foo) var x, y;",
+            output: null,
+            options: [{ var: "never" }],
+            errors: [{
+                messageId: "split",
+                data: { type: "var" },
+                type: "VariableDeclaration"
+            }]
+        },
+        {
+            code: "if (foo) var x, y;",
+            output: null,
+            options: [{ uninitialized: "never" }],
+            errors: [{
+                messageId: "splitUninitialized",
+                data: { type: "var" },
+                type: "VariableDeclaration"
+            }]
+        },
+        {
+            code: "if (foo) var x = 1, y = 1;",
+            output: null,
+            options: [{ initialized: "never" }],
+            errors: [{
+                messageId: "splitInitialized",
+                data: { type: "var" },
+                type: "VariableDeclaration"
+            }]
+        },
+        {
+            code: "if (foo) {} else var x, y;",
+            output: null,
+            options: ["never"],
+            errors: [{
+                messageId: "split",
+                data: { type: "var" },
+                type: "VariableDeclaration"
+            }]
+        },
+        {
+            code: "while (foo) var x, y;",
+            output: null,
+            options: ["never"],
+            errors: [{
+                messageId: "split",
+                data: { type: "var" },
+                type: "VariableDeclaration"
+            }]
+        },
+        {
+            code: "do var x, y; while (foo);",
+            output: null,
+            options: ["never"],
+            errors: [{
+                messageId: "split",
+                data: { type: "var" },
+                type: "VariableDeclaration"
+            }]
+        },
+        {
+            code: "do var x = f(), y = b(); while (x < y);",
+            output: null,
+            options: ["never"],
+            errors: [{
+                messageId: "split",
+                data: { type: "var" },
+                type: "VariableDeclaration"
+            }]
+        },
+        {
+            code: "for (;;) var x, y;",
+            output: null,
+            options: ["never"],
+            errors: [{
+                messageId: "split",
+                data: { type: "var" },
+                type: "VariableDeclaration"
+            }]
+        },
+        {
+            code: "for (foo in bar) var x, y;",
+            output: null,
+            options: ["never"],
+            errors: [{
+                messageId: "split",
+                data: { type: "var" },
+                type: "VariableDeclaration"
+            }]
+        },
+        {
+            code: "for (foo of bar) var x, y;",
+            output: null,
+            options: ["never"],
+            errors: [{
+                messageId: "split",
+                data: { type: "var" },
+                type: "VariableDeclaration"
+            }]
+        },
+        {
+            code: "with (foo) var x, y;",
+            output: null,
+            options: ["never"],
+            errors: [{
+                messageId: "split",
+                data: { type: "var" },
+                type: "VariableDeclaration"
+            }]
+        },
+        {
+            code: "label: var x, y;",
+            output: null,
+            options: ["never"],
+            errors: [{
+                messageId: "split",
+                data: { type: "var" },
+                type: "VariableDeclaration"
+            }]
         }
     ]
 });