diff --git a/src/compiler/compile/nodes/Element.ts b/src/compiler/compile/nodes/Element.ts
index 7a70e603a77f..ab5ddd2f072f 100644
--- a/src/compiler/compile/nodes/Element.ts
+++ b/src/compiler/compile/nodes/Element.ts
@@ -424,6 +424,25 @@ export default class Element extends Node {
 				});
 			}
 
+			if (name === "onmouseover") {
+				if (!this.attributes.find(i => i.name === 'onFocus')) {
+					component.warn(attribute, {
+						code: `a11y-mouse-events-have-key-events`,
+						message: `A11y: onMouseOver must be accompanied by onFocus for accessibility.`
+					});
+				}
+			}
+
+			if (name === "onmouseout") {
+				if (!this.attributes.find(i => i.name === 'onBlur')) {
+					component.warn(attribute, {
+						code: `a11y-mouse-events-have-key-events`,
+						message: `A11y: onMouseOut must be accompanied by onBlur for accessibility.`
+					});
+				}
+			}
+
+
 			attribute_map.set(attribute.name, attribute);
 		});
 	}
diff --git a/test/validator/samples/a11y-mouse-events-have-key-events/input.svelte b/test/validator/samples/a11y-mouse-events-have-key-events/input.svelte
new file mode 100644
index 000000000000..efdf95a0a1e3
--- /dev/null
+++ b/test/validator/samples/a11y-mouse-events-have-key-events/input.svelte
@@ -0,0 +1,4 @@
+<div onMouseOver={ () => void 0 } />
+<div onMouseOut={ () => void 0 } />
+<div onMouseOver={ () => void 0 } onFocus={ () => void 0 } />
+<div onMouseOut={ () => void 0 } onBlur={ () => void 0 } />
diff --git a/test/validator/samples/a11y-mouse-events-have-key-events/warnings.json b/test/validator/samples/a11y-mouse-events-have-key-events/warnings.json
new file mode 100644
index 000000000000..33617735c871
--- /dev/null
+++ b/test/validator/samples/a11y-mouse-events-have-key-events/warnings.json
@@ -0,0 +1,32 @@
+[
+  {
+    "code": "a11y-mouse-events-have-key-events",
+    "end": {
+      "character": 33,
+      "column": 33,
+      "line": 1
+    },
+    "message": "A11y: onMouseOver must be accompanied by onFocus for accessibility.",
+    "pos": 5,
+    "start": {
+      "character": 5,
+      "column": 5,
+      "line": 1
+    }
+  },
+  {
+    "code": "a11y-mouse-events-have-key-events",
+    "end": {
+      "character": 69,
+      "column": 32,
+      "line": 2
+    },
+    "message": "A11y: onMouseOut must be accompanied by onBlur for accessibility.",
+    "pos": 42,
+    "start": {
+      "character": 42,
+      "column": 5,
+      "line": 2
+    }
+  }
+]