diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index ad106c5..317da29 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -48,6 +48,10 @@ jobs:
         if: matrix.toolchain != '1.36.0'
         run: cargo test --verbose --features serde
 
+      - name: Cargo test w/ malloc_size_of
+        if: matrix.toolchain != '1.36.0'
+        run: cargo test --verbose --features malloc_size_of
+
       - name: Cargo check w/o default features
         if: matrix.toolchain == 'nightly'
         run: cargo check --verbose --no-default-features
diff --git a/Cargo.toml b/Cargo.toml
index ae2a9fc..f7afed4 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -27,6 +27,7 @@ debugger_visualizer = []
 
 [dependencies]
 serde = { version = "1", optional = true, default-features = false }
+malloc_size_of = { version = "0.1", optional = true, default-features = false }
 arbitrary = { version = "1", optional = true }
 
 [dev_dependencies]
diff --git a/fuzz/Cargo.lock b/fuzz/Cargo.lock
index 5253e47..fb73e46 100644
--- a/fuzz/Cargo.lock
+++ b/fuzz/Cargo.lock
@@ -1,6 +1,6 @@
 # This file is automatically @generated by Cargo.
 # It is not intended for manual editing.
-version = 3
+version = 4
 
 [[package]]
 name = "afl"
@@ -87,9 +87,9 @@ dependencies = [
 
 [[package]]
 name = "honggfuzz"
-version = "0.5.55"
+version = "0.5.56"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "848e9c511092e0daa0a35a63e8e6e475a3e8f870741448b9f6028d69b142f18e"
+checksum = "7c76b6234c13c9ea73946d1379d33186151148e0da231506b964b44f3d023505"
 dependencies = [
  "arbitrary",
  "lazy_static",
@@ -105,15 +105,15 @@ checksum = "e2abad23fbc42b3700f2f279844dc832adb2b2eb069b2df918f455c4e18cc646"
 
 [[package]]
 name = "libc"
-version = "0.2.146"
+version = "0.2.169"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "f92be4933c13fd498862a9e02a3055f8a8d9c039ce33db97306fd5a6caa7f29b"
+checksum = "b5aba8db14291edd000dfcc4d620c7ebfb122c613afb886ca8803fa4e128a20a"
 
 [[package]]
 name = "memmap2"
-version = "0.5.10"
+version = "0.9.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "83faa42c0a078c393f6b29d5db232d8be22776a891f8f56e5284faee4a20b327"
+checksum = "fd3f7eed9d3848f8b98834af67102b720745c4ec028fcd0aa0239277e7de374f"
 dependencies = [
  "libc",
 ]
@@ -159,7 +159,7 @@ checksum = "388a1df253eca08550bef6c72392cfe7c30914bf41df5269b68cbd6ff8f570a3"
 
 [[package]]
 name = "smallvec"
-version = "1.10.0"
+version = "1.13.2"
 
 [[package]]
 name = "smallvec-fuzz"
diff --git a/src/lib.rs b/src/lib.rs
index 1ea3deb..af976eb 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -126,6 +126,9 @@ use core::ops::{self, Range, RangeBounds};
 use core::ptr::{self, NonNull};
 use core::slice::{self, SliceIndex};
 
+#[cfg(feature = "malloc_size_of")]
+use malloc_size_of::{MallocShallowSizeOf, MallocSizeOf, MallocSizeOfOps};
+
 #[cfg(feature = "serde")]
 use serde::{
     de::{Deserialize, Deserializer, SeqAccess, Visitor},
@@ -1971,6 +1974,32 @@ where
     }
 }
 
+#[cfg(feature = "malloc_size_of")]
+impl<A: Array> MallocShallowSizeOf for SmallVec<A> {
+    fn shallow_size_of(&self, ops: &mut MallocSizeOfOps) -> usize {
+        if self.spilled() {
+            unsafe { ops.malloc_size_of(self.as_ptr()) }
+        } else {
+            0
+        }
+    }
+}
+
+#[cfg(feature = "malloc_size_of")]
+impl<A> MallocSizeOf for SmallVec<A>
+where
+    A: Array,
+    A::Item: MallocSizeOf,
+{
+    fn size_of(&self, ops: &mut MallocSizeOfOps) -> usize {
+        let mut n = self.shallow_size_of(ops);
+        for elem in self.iter() {
+            n += elem.size_of(ops);
+        }
+        n
+    }
+}
+
 #[cfg(feature = "specialization")]
 trait SpecFrom<A: Array, S> {
     fn spec_from(slice: S) -> SmallVec<A>;