diff --git a/src/_insertAfter.js b/src/_insertAfter.js
new file mode 100644
index 0000000..5c1e66c
--- /dev/null
+++ b/src/_insertAfter.js
@@ -0,0 +1,14 @@
+import assert from 'assert';
+import Node from './Node.js';
+import _insertBetween from './_insertBetween.js';
+
+/**
+ * _insertAfter.
+ *
+ * @param {Node} x
+ * @param {any} value
+ */
+export default function _insertAfter(x, value) {
+	assert(x instanceof Node);
+	return _insertBetween(x, x.next, value);
+}
diff --git a/src/_insertBefore.js b/src/_insertBefore.js
new file mode 100644
index 0000000..b3127c9
--- /dev/null
+++ b/src/_insertBefore.js
@@ -0,0 +1,14 @@
+import assert from 'assert';
+import Node from './Node.js';
+import _insertBetween from './_insertBetween.js';
+
+/**
+ * _insertBefore.
+ *
+ * @param {Node} x
+ * @param {any} value
+ */
+export default function _insertBefore(x, value) {
+	assert(x instanceof Node);
+	return _insertBetween(x.prev, x, value);
+}
diff --git a/src/_insertBetween.js b/src/_insertBetween.js
new file mode 100644
index 0000000..21c215e
--- /dev/null
+++ b/src/_insertBetween.js
@@ -0,0 +1,18 @@
+import assert from 'assert';
+import Node from './Node.js';
+
+/**
+ * _insertBetween.
+ *
+ * @param {Node} x
+ * @param {Node} y
+ * @param {any} value
+ */
+export default function _insertBetween(x, y, value) {
+	assert(x instanceof Node);
+	assert(y instanceof Node);
+	const z = new Node(value, x, y);
+	x.next = z;
+	y.prev = z;
+	return z;
+}
diff --git a/src/index.js b/src/index.js
index 6654aa7..879c158 100644
--- a/src/index.js
+++ b/src/index.js
@@ -2,6 +2,9 @@ export {default as Node} from './Node.js';
 export {default as _concat} from './_concat.js';
 export {default as _erase} from './_erase.js';
 export {default as _extend} from './_extend.js';
+export {default as _insertAfter} from './_insertAfter.js';
+export {default as _insertBefore} from './_insertBefore.js';
+export {default as _insertBetween} from './_insertBetween.js';
 export {default as _iter} from './_iter.js';
 export {default as _iter_fast} from './_iter_fast.js';
 export {default as _last} from './_last.js';
diff --git a/test/src/insert.js b/test/src/insert.js
new file mode 100644
index 0000000..8ba3cf3
--- /dev/null
+++ b/test/src/insert.js
@@ -0,0 +1,19 @@
+import test from 'ava';
+
+import {list} from '@iterable-iterator/list';
+
+import {_insertAfter, _insertBefore, from, values} from '#module';
+
+test('insertAfter', (t) => {
+	const x = from('abc');
+	const y = _insertAfter(x, 'z');
+	t.is(y.value, 'z');
+	t.is(list(values(x)).join(''), 'azbc');
+});
+
+test('insertBefore', (t) => {
+	const x = from('abc');
+	const y = _insertBefore(x.next, 'z');
+	t.is(y.value, 'z');
+	t.is(list(values(x)).join(''), 'azbc');
+});