diff --git a/libmemunreachable/Allocator.h b/libmemunreachable/Allocator.h
index a8f579e..5390739 100644
--- a/libmemunreachable/Allocator.h
+++ b/libmemunreachable/Allocator.h
@@ -109,13 +109,13 @@
   }
 
   // Construct an STLAllocator on top of a Heap
-  STLAllocator(const Heap& heap) :
+  STLAllocator(const Heap& heap) :  // NOLINT, implicit
       heap_(heap) {
   }
 
   // Rebind an STLAllocator from an another STLAllocator
   template<typename U>
-  STLAllocator(const STLAllocator<U>& other) :
+  STLAllocator(const STLAllocator<U>& other) :  // NOLINT, implicit
       heap_(other.heap_) {
   }
 
@@ -155,12 +155,12 @@
  public:
   ~Allocator() {}
 
-  Allocator(const Heap& other) :
+  Allocator(const Heap& other) : // NOLINT, implicit
       STLAllocator<T>(other) {
   }
 
   template<typename U>
-  Allocator(const STLAllocator<U>& other) :
+  Allocator(const STLAllocator<U>& other) :  // NOLINT, implicit
       STLAllocator<T>(other) {
   }
 
diff --git a/libmemunreachable/HeapWalker.h b/libmemunreachable/HeapWalker.h
index 3c1b513..b25696f 100644
--- a/libmemunreachable/HeapWalker.h
+++ b/libmemunreachable/HeapWalker.h
@@ -48,7 +48,7 @@
 
 class HeapWalker {
  public:
-  HeapWalker(Allocator<HeapWalker> allocator) : allocator_(allocator),
+  explicit HeapWalker(Allocator<HeapWalker> allocator) : allocator_(allocator),
     allocations_(allocator), allocation_bytes_(0),
 	roots_(allocator), root_vals_(allocator),
 	segv_handler_(allocator), walking_ptr_(0) {
diff --git a/libmemunreachable/LeakFolding.h b/libmemunreachable/LeakFolding.h
index 732d3f2..9c6a525 100644
--- a/libmemunreachable/LeakFolding.h
+++ b/libmemunreachable/LeakFolding.h
@@ -54,7 +54,7 @@
     bool dominator;
     SCCInfo* accumulator;
 
-    SCCInfo(Allocator<SCCInfo> allocator) : node(this, allocator),
+    explicit SCCInfo(Allocator<SCCInfo> allocator) : node(this, allocator),
         count(0), size(0), cuumulative_count(0), cuumulative_size(0),
         dominator(false), accumulator(nullptr) {}
    private:
diff --git a/libmemunreachable/LinkedList.h b/libmemunreachable/LinkedList.h
index 3e44035..132842d 100644
--- a/libmemunreachable/LinkedList.h
+++ b/libmemunreachable/LinkedList.h
@@ -21,7 +21,7 @@
 class LinkedList {
 public:
     LinkedList() : next_(this), prev_(this), data_() {}
-    LinkedList(T data) : LinkedList() {
+    explicit LinkedList(T data) : LinkedList() {
         data_ = data;
     }
     ~LinkedList() {}
diff --git a/libmemunreachable/PtracerThread.h b/libmemunreachable/PtracerThread.h
index 4d6ca9a..f88b599 100644
--- a/libmemunreachable/PtracerThread.h
+++ b/libmemunreachable/PtracerThread.h
@@ -32,7 +32,7 @@
 // the parent.
 class PtracerThread {
  public:
-  PtracerThread(const std::function<int()>& func);
+  explicit PtracerThread(const std::function<int()>& func);
   ~PtracerThread();
   bool Start();
   int Join();
diff --git a/libmemunreachable/ScopedDisableMalloc.h b/libmemunreachable/ScopedDisableMalloc.h
index 4f96376..758d317 100644
--- a/libmemunreachable/ScopedDisableMalloc.h
+++ b/libmemunreachable/ScopedDisableMalloc.h
@@ -74,7 +74,7 @@
 
 class ScopedDisableMallocTimeout {
  public:
-  ScopedDisableMallocTimeout(std::chrono::milliseconds timeout = std::chrono::milliseconds(2000)) :
+  explicit ScopedDisableMallocTimeout(std::chrono::milliseconds timeout = std::chrono::milliseconds(2000)) :
     timeout_(timeout), timed_out_(false), disable_malloc_() {
     Disable();
   }
diff --git a/libmemunreachable/ScopedSignalHandler.h b/libmemunreachable/ScopedSignalHandler.h
index e006d43..1fd9d4d 100644
--- a/libmemunreachable/ScopedSignalHandler.h
+++ b/libmemunreachable/ScopedSignalHandler.h
@@ -30,7 +30,7 @@
  public:
   using Fn = std::function<void(ScopedSignalHandler&, int, siginfo_t*, void*)>;
 
-  ScopedSignalHandler(Allocator<Fn> allocator) : allocator_(allocator), signal_(-1) {}
+  explicit ScopedSignalHandler(Allocator<Fn> allocator) : allocator_(allocator), signal_(-1) {}
   ~ScopedSignalHandler() {
     reset();
   }
diff --git a/libmemunreachable/Semaphore.h b/libmemunreachable/Semaphore.h
index 45e8c81..6bcf4ea 100644
--- a/libmemunreachable/Semaphore.h
+++ b/libmemunreachable/Semaphore.h
@@ -24,7 +24,7 @@
 
 class Semaphore {
  public:
-  Semaphore(int count = 0) : count_(count) {}
+  explicit Semaphore(int count = 0) : count_(count) {}
   ~Semaphore() = default;
 
   void Wait(std::chrono::milliseconds ms) {
diff --git a/libmemunreachable/Tarjan.h b/libmemunreachable/Tarjan.h
index d7ecdb9..dcd139a 100644
--- a/libmemunreachable/Tarjan.h
+++ b/libmemunreachable/Tarjan.h
@@ -62,7 +62,7 @@
 template<class T>
 class TarjanAlgorithm {
  public:
-  TarjanAlgorithm(Allocator<void> allocator) : index_(0),
+  explicit TarjanAlgorithm(Allocator<void> allocator) : index_(0),
     stack_(allocator), components_(allocator) {}
 
   void Execute(Graph<T>& graph, SCCList<T>& out);
diff --git a/libmemunreachable/tests/MemUnreachable_test.cpp b/libmemunreachable/tests/MemUnreachable_test.cpp
index 0747b12..2ae3db8 100644
--- a/libmemunreachable/tests/MemUnreachable_test.cpp
+++ b/libmemunreachable/tests/MemUnreachable_test.cpp
@@ -27,7 +27,7 @@
 
 class HiddenPointer {
  public:
-  HiddenPointer(size_t size = 256) {
+  explicit HiddenPointer(size_t size = 256) {
     Set(malloc(size));
   }
   ~HiddenPointer() {