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diff --git a/pw_allocator/simple_allocator_test.cc b/pw_allocator/simple_allocator_test.cc
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+++ b/pw_allocator/simple_allocator_test.cc
@@ -0,0 +1,66 @@
+// Copyright 2023 The Pigweed Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License"); you may not
+// use this file except in compliance with the License. You may obtain a copy of
+// the License at
+//
+//     https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+// WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+// License for the specific language governing permissions and limitations under
+// the License.
+
+#include "pw_allocator/simple_allocator.h"
+
+#include "gtest/gtest.h"
+#include "pw_allocator/allocator_testing.h"
+
+namespace pw::allocator {
+
+// Size of the memory region to use in the tests below.
+constexpr size_t kCapacity = 256;
+
+// An `SimpleAllocator` that is automatically initialized on construction.
+class SimpleAllocatorWithBuffer
+    : public test::WithBuffer<SimpleAllocator, kCapacity> {
+ public:
+  SimpleAllocatorWithBuffer() {
+    EXPECT_EQ((*this)->Init(ByteSpan(this->data(), this->size())), OkStatus());
+  }
+};
+
+// This is not meant to be a rigorous unit test of individual behaviors, as much
+// as simply a way to demonstrate and exercise the simple allocator.
+TEST(SimpleAllocatorTest, AllocateResizeDeallocate) {
+  SimpleAllocatorWithBuffer allocator;
+
+  // Can allocate usable memory.
+  constexpr size_t kSize1 = kCapacity / 4;
+  constexpr Layout layout1 = Layout::Of<std::byte[kSize1]>();
+  auto* ptr = static_cast<std::byte*>(allocator->Allocate(layout1));
+  ASSERT_NE(ptr, nullptr);
+  memset(ptr, 0x5A, kSize1);
+
+  // Can shrink memory. Contents are preserved.
+  constexpr size_t kSize2 = kCapacity / 8;
+  constexpr Layout layout2 = Layout::Of<std::byte[kSize2]>();
+  EXPECT_TRUE(allocator->Resize(ptr, layout1, layout2.size()));
+  for (size_t i = 0; i < kSize2; ++i) {
+    EXPECT_EQ(size_t(ptr[i]), 0x5Au);
+  }
+
+  // Can grow memory. Contents are preserved.
+  constexpr size_t kSize3 = kCapacity / 2;
+  constexpr Layout layout3 = Layout::Of<std::byte[kSize3]>();
+  EXPECT_TRUE(allocator->Resize(ptr, layout2, layout3.size()));
+  for (size_t i = 0; i < kSize2; ++i) {
+    EXPECT_EQ(size_t(ptr[i]), 0x5Au);
+  }
+
+  // Can free memory.
+  allocator->Deallocate(ptr, layout3);
+}
+
+}  // namespace pw::allocator