diff --git a/lib/std/bit_set.zig b/lib/std/bit_set.zig
index d87c1d26f6..61aca5f9fd 100644
--- a/lib/std/bit_set.zig
+++ b/lib/std/bit_set.zig
@@ -859,6 +859,18 @@ pub const DynamicBitSetUnmanaged = struct {
         self.masks[maskIndex(index)] &= ~maskBit(index);
     }
 
+    /// Set all bits to 0.
+    pub fn unsetAll(self: *Self) void {
+        const masks_len = numMasks(self.bit_length);
+        @memset(self.masks[0..masks_len], 0);
+    }
+
+    /// Set all bits to 1.
+    pub fn setAll(self: *Self) void {
+        const masks_len = numMasks(self.bit_length);
+        @memset(self.masks[0..masks_len], std.math.maxInt(MaskInt));
+    }
+
     /// Flips a specific bit in the bit set
     pub fn toggle(self: *Self, index: usize) void {
         assert(index < self.bit_length);