diff --git a/libbpf_android/BpfMapTest.cpp b/libbpf_android/BpfMapTest.cpp
index 895dda6..94d273e 100644
--- a/libbpf_android/BpfMapTest.cpp
+++ b/libbpf_android/BpfMapTest.cpp
@@ -52,7 +52,13 @@
 class BpfMapTest : public testing::Test {
   protected:
     BpfMapTest() {}
-    int mMapFd;
+
+    // SetUp() will always populate this with a map, but only some tests will use it.
+    // They may use it once via 'mMapFd.release()', or multiple times via 'dup(mMapFd)'
+    // to initialize a BpfMap object.
+    // If it's not used or only dup'ed then TearDown() will close() it, otherwise
+    // whoever got ownership via mMapFd.release() will close() it - possibly much earlier.
+    unique_fd mMapFd;
 
     void SetUp() {
         SKIP_IF_BPF_NOT_SUPPORTED;
@@ -61,9 +67,9 @@
         if (!access(PINNED_MAP_PATH, R_OK)) {
             EXPECT_EQ(0, remove(PINNED_MAP_PATH));
         }
-        mMapFd = createMap(BPF_MAP_TYPE_HASH, sizeof(uint32_t), sizeof(uint32_t), TEST_MAP_SIZE,
-                           BPF_F_NO_PREALLOC);
-        EXPECT_LE(0, mMapFd);
+        mMapFd.reset(createMap(BPF_MAP_TYPE_HASH, sizeof(uint32_t), sizeof(uint32_t), TEST_MAP_SIZE,
+                               BPF_F_NO_PREALLOC));
+        ASSERT_LE(0, mMapFd);
     }
 
     void TearDown() {
@@ -72,7 +78,8 @@
         if (!access(PINNED_MAP_PATH, R_OK)) {
             EXPECT_EQ(0, remove(PINNED_MAP_PATH));
         }
-        close(mMapFd);
+
+        mMapFd.reset(-1);  // close(mMapFd) if still open
     }
 
     void checkMapInvalid(BpfMap<uint32_t, uint32_t>& map) {
@@ -117,7 +124,7 @@
     BpfMap<uint32_t, uint32_t> testMap1;
     checkMapInvalid(testMap1);
 
-    BpfMap<uint32_t, uint32_t> testMap2(mMapFd);
+    BpfMap<uint32_t, uint32_t> testMap2(mMapFd.release());
     checkMapValid(testMap2);
 
     BpfMap<uint32_t, uint32_t> testMap3(BPF_MAP_TYPE_HASH, TEST_MAP_SIZE, BPF_F_NO_PREALLOC);
@@ -127,7 +134,7 @@
 TEST_F(BpfMapTest, basicHelpers) {
     SKIP_IF_BPF_NOT_SUPPORTED;
 
-    BpfMap<uint32_t, uint32_t> testMap(mMapFd);
+    BpfMap<uint32_t, uint32_t> testMap(mMapFd.release());
     uint32_t key = TEST_KEY1;
     uint32_t value_write = TEST_VALUE1;
     writeToMapAndCheck(testMap, key, value_write);
@@ -144,21 +151,21 @@
     SKIP_IF_BPF_NOT_SUPPORTED;
 
     BpfMap<uint32_t, uint32_t> testMap;
-    testMap.reset(mMapFd);
+    testMap.reset(mMapFd.release());
     uint32_t key = TEST_KEY1;
     uint32_t value_write = TEST_VALUE1;
     writeToMapAndCheck(testMap, key, value_write);
+
     testMap.reset();
     checkMapInvalid(testMap);
-    unique_fd invalidFd(mMapFd);
-    ASSERT_GT(0, findMapEntry(invalidFd, &key, &value_write));
+    ASSERT_GT(0, findMapEntry(testMap.getMap(), &key, &value_write));
     ASSERT_EQ(EBADF, errno);
 }
 
 TEST_F(BpfMapTest, moveConstructor) {
     SKIP_IF_BPF_NOT_SUPPORTED;
 
-    BpfMap<uint32_t, uint32_t> testMap1(mMapFd);
+    BpfMap<uint32_t, uint32_t> testMap1(mMapFd.release());
     BpfMap<uint32_t, uint32_t> testMap2;
     testMap2 = std::move(testMap1);
     uint32_t key = TEST_KEY1;
@@ -188,7 +195,7 @@
 TEST_F(BpfMapTest, iterate) {
     SKIP_IF_BPF_NOT_SUPPORTED;
 
-    BpfMap<uint32_t, uint32_t> testMap(mMapFd);
+    BpfMap<uint32_t, uint32_t> testMap(mMapFd.release());
     populateMap(TEST_MAP_SIZE, testMap);
     int totalCount = 0;
     int totalSum = 0;
@@ -208,7 +215,7 @@
 TEST_F(BpfMapTest, iterateWithValue) {
     SKIP_IF_BPF_NOT_SUPPORTED;
 
-    BpfMap<uint32_t, uint32_t> testMap(mMapFd);
+    BpfMap<uint32_t, uint32_t> testMap(mMapFd.release());
     populateMap(TEST_MAP_SIZE, testMap);
     int totalCount = 0;
     int totalSum = 0;
@@ -230,7 +237,7 @@
 TEST_F(BpfMapTest, mapIsEmpty) {
     SKIP_IF_BPF_NOT_SUPPORTED;
 
-    BpfMap<uint32_t, uint32_t> testMap(mMapFd);
+    BpfMap<uint32_t, uint32_t> testMap(mMapFd.release());
     expectMapEmpty(testMap);
     uint32_t key = TEST_KEY1;
     uint32_t value_write = TEST_VALUE1;
@@ -262,7 +269,7 @@
 TEST_F(BpfMapTest, mapClear) {
     SKIP_IF_BPF_NOT_SUPPORTED;
 
-    BpfMap<uint32_t, uint32_t> testMap(mMapFd);
+    BpfMap<uint32_t, uint32_t> testMap(mMapFd.release());
     populateMap(TEST_MAP_SIZE, testMap);
     auto isEmpty = testMap.isEmpty();
     ASSERT_TRUE(isOk(isEmpty));
diff --git a/libbpf_android/include/bpf/BpfMap.h b/libbpf_android/include/bpf/BpfMap.h
index d47698e..a894b57 100644
--- a/libbpf_android/include/bpf/BpfMap.h
+++ b/libbpf_android/include/bpf/BpfMap.h
@@ -46,8 +46,19 @@
 template <class Key, class Value>
 class BpfMap {
   public:
-    BpfMap<Key, Value>() : mMapFd(-1){};
+    BpfMap<Key, Value>() {};
     explicit BpfMap<Key, Value>(int fd) : mMapFd(fd){};
+
+    // We could technically implement this constructor either with
+    //   : mMapFd(dup(fd)) {}        // fd valid in caller, we have our own local copy
+    // or
+    //   : mMapFd(fd.release()) {}   // fd no longer valid in caller, we 'stole' it
+    //
+    // However, I think we're much better off with a compile time failure, since
+    // it's better for whoever passes in a unique_fd to think twice about whether
+    // they're trying to pass in ownership or not.
+    explicit BpfMap<Key, Value>(base::unique_fd fd) = delete;
+
     BpfMap<Key, Value>(bpf_map_type map_type, uint32_t max_entries, uint32_t map_flags) {
         int map_fd = createMap(map_type, sizeof(Key), sizeof(Value), max_entries, map_flags);
         if (map_fd < 0) {