diff --git a/lib/std/collections/bitmap.c3 b/lib/std/collections/bitmap.c3
new file mode 100644
index 000000000..5f5bba9dc
--- /dev/null
+++ b/lib/std/collections/bitmap.c3
@@ -0,0 +1,78 @@
+/**
+ * @require Type.kindof == UNSIGNED_INT
+ **/
+module std::collections::bitmap(<Type>);
+import std::collections::list;
+
+def BitmapList = List(<Type>);
+
+struct Bitmap
+{
+	BitmapList data;
+}
+
+fn void Bitmap.init(&self, usz initial_capacity = 1, Allocator* using = mem::heap())
+{
+	self.data.init(initial_capacity, using);
+}
+
+fn void Bitmap.tinit(&self)
+{
+	self.init(.using = mem::temp());
+}
+
+fn usz Bitmap.cardinality(&self)
+{
+	usz n;
+	foreach (x : self.data)
+	{
+		n += x.popcount();
+	}
+	return n;
+}
+
+fn void Bitmap.set(&self, usz i)
+{
+	usz q = i / Type.sizeof;
+	usz r = i % Type.sizeof;
+	if (q >= self.data.len())
+	{
+		self.data.reserve(q + 1);
+		self.data.size = q + 1;
+	}
+	self.data.set(q, self.data[q] | (1 << r));
+}
+
+fn void Bitmap.unset(&self, usz i)
+{
+	usz q = i / Type.sizeof;
+	usz r = i % Type.sizeof;
+	if (q >= self.data.len()) return;
+	self.data.set(q, self.data[q] &~ (1 << r));
+}
+
+fn bool Bitmap.get(&self, usz i)
+{
+	usz q = i / Type.sizeof;
+	usz r = i % Type.sizeof;
+	if (q >= self.data.len()) return false;
+	return self.data[q] & (1 << r) != 0;
+}
+
+fn usz Bitmap.len(&self) @operator(len)
+{
+	usz n = self.data.len();
+	if (n > 0) n -= self.data[n - 1].ctz();
+	return n;
+}
+
+fn bool Bitmap.get_bool(&self, usz i) @operator([]) @inline
+{
+	return self.get(i);
+}
+
+fn void Bitmap.set_bool(&self, usz i, bool value) @operator([]=) @inline
+{
+	if (value) return self.set(i);
+	self.unset(i);
+}
\ No newline at end of file
diff --git a/test/unit/stdlib/collections/bitmap.c3 b/test/unit/stdlib/collections/bitmap.c3
new file mode 100644
index 000000000..c068cbd66
--- /dev/null
+++ b/test/unit/stdlib/collections/bitmap.c3
@@ -0,0 +1,46 @@
+module list_test @test;
+import std::collections::bitmap;
+import std::collections::list;
+import std::io;
+
+def Bitmap = Bitmap(<char>);
+def List = List(<usz>);
+
+fn void! set_get()
+{
+	Bitmap bm;
+	bm.tinit();
+	assert(bm.len() == 0);
+
+	assert(!bm.get(0));
+	bm.set(0);
+	assert(bm.get(0));
+	assert(bm.cardinality() == 1);
+
+	assert(!bm.get(2000));
+	bm.set(2000);
+	assert(bm.get(2000));
+	assert(bm.cardinality() == 2);
+
+	List found;
+	found.tinit();
+	foreach (i, x : bm)
+	{
+		switch (i)
+		{
+			case 0:
+			case 2000:
+				assert(x);
+				found.push(i);
+			default:
+				assert(!x);
+		}
+	}
+	assert(found.array_view() == usz[]{0, 2000});
+
+	bm.unset(0);
+	assert(!bm.get(0));
+	bm.unset(2000);
+	assert(!bm.get(2000));
+	assert(bm.cardinality() == 0);
+}
\ No newline at end of file