diff --git a/src/citra_qt/bootmanager.h b/src/citra_qt/bootmanager.h
index 92da1f5f3..af52f369b 100644
--- a/src/citra_qt/bootmanager.h
+++ b/src/citra_qt/bootmanager.h
@@ -23,7 +23,7 @@ class EmuThread : public QThread {
     Q_OBJECT
 
 public:
-    EmuThread(GRenderWindow* render_window);
+    explicit EmuThread(GRenderWindow* render_window);
 
     /**
      * Start emulation (on new thread)
diff --git a/src/citra_qt/debugger/callstack.h b/src/citra_qt/debugger/callstack.h
index b08a8357e..f04ab9c7e 100644
--- a/src/citra_qt/debugger/callstack.h
+++ b/src/citra_qt/debugger/callstack.h
@@ -13,7 +13,7 @@ class CallstackWidget : public QDockWidget {
     Q_OBJECT
 
 public:
-    CallstackWidget(QWidget* parent = nullptr);
+    explicit CallstackWidget(QWidget* parent = nullptr);
 
 public slots:
     void OnDebugModeEntered();
diff --git a/src/citra_qt/debugger/disassembler.h b/src/citra_qt/debugger/disassembler.h
index 2ca6c2bd4..895f6ac89 100644
--- a/src/citra_qt/debugger/disassembler.h
+++ b/src/citra_qt/debugger/disassembler.h
@@ -17,7 +17,7 @@ class DisassemblerModel : public QAbstractListModel {
     Q_OBJECT
 
 public:
-    DisassemblerModel(QObject* parent);
+    explicit DisassemblerModel(QObject* parent);
 
     int columnCount(const QModelIndex& parent = QModelIndex()) const override;
     int rowCount(const QModelIndex& parent = QModelIndex()) const override;
diff --git a/src/citra_qt/debugger/graphics.h b/src/citra_qt/debugger/graphics.h
index bedf3e596..8837fb792 100644
--- a/src/citra_qt/debugger/graphics.h
+++ b/src/citra_qt/debugger/graphics.h
@@ -13,7 +13,7 @@ class GPUCommandStreamItemModel : public QAbstractListModel,
     Q_OBJECT
 
 public:
-    GPUCommandStreamItemModel(QObject* parent);
+    explicit GPUCommandStreamItemModel(QObject* parent);
 
     int rowCount(const QModelIndex& parent = QModelIndex()) const override;
     QVariant data(const QModelIndex& index, int role = Qt::DisplayRole) const override;
diff --git a/src/citra_qt/debugger/graphics_breakpoints.h b/src/citra_qt/debugger/graphics_breakpoints.h
index 5fc40c916..bec72a2db 100644
--- a/src/citra_qt/debugger/graphics_breakpoints.h
+++ b/src/citra_qt/debugger/graphics_breakpoints.h
@@ -20,8 +20,8 @@ class GraphicsBreakPointsWidget : public QDockWidget, Pica::DebugContext::BreakP
     using Event = Pica::DebugContext::Event;
 
 public:
-    GraphicsBreakPointsWidget(std::shared_ptr<Pica::DebugContext> debug_context,
-                              QWidget* parent = nullptr);
+    explicit GraphicsBreakPointsWidget(std::shared_ptr<Pica::DebugContext> debug_context,
+                                       QWidget* parent = nullptr);
 
     void OnPicaBreakPointHit(Pica::DebugContext::Event event, void* data) override;
     void OnPicaResume() override;
diff --git a/src/citra_qt/debugger/graphics_cmdlists.h b/src/citra_qt/debugger/graphics_cmdlists.h
index fa2b9122b..8f40b94c5 100644
--- a/src/citra_qt/debugger/graphics_cmdlists.h
+++ b/src/citra_qt/debugger/graphics_cmdlists.h
@@ -20,7 +20,7 @@ public:
         CommandIdRole = Qt::UserRole,
     };
 
-    GPUCommandListModel(QObject* parent);
+    explicit GPUCommandListModel(QObject* parent);
 
     int columnCount(const QModelIndex& parent = QModelIndex()) const override;
     int rowCount(const QModelIndex& parent = QModelIndex()) const override;
@@ -39,7 +39,7 @@ class GPUCommandListWidget : public QDockWidget {
     Q_OBJECT
 
 public:
-    GPUCommandListWidget(QWidget* parent = nullptr);
+    explicit GPUCommandListWidget(QWidget* parent = nullptr);
 
 public slots:
     void OnToggleTracing();
diff --git a/src/citra_qt/debugger/graphics_surface.h b/src/citra_qt/debugger/graphics_surface.h
index 21e6b5b8b..19ffb55fb 100644
--- a/src/citra_qt/debugger/graphics_surface.h
+++ b/src/citra_qt/debugger/graphics_surface.h
@@ -18,7 +18,8 @@ class SurfacePicture : public QLabel {
     Q_OBJECT
 
 public:
-    SurfacePicture(QWidget* parent = 0, GraphicsSurfaceWidget* surface_widget = nullptr);
+    explicit SurfacePicture(QWidget* parent = nullptr,
+                            GraphicsSurfaceWidget* surface_widget = nullptr);
     ~SurfacePicture();
 
 protected slots:
@@ -71,8 +72,8 @@ class GraphicsSurfaceWidget : public BreakPointObserverDock {
     static unsigned int NibblesPerPixel(Format format);
 
 public:
-    GraphicsSurfaceWidget(std::shared_ptr<Pica::DebugContext> debug_context,
-                          QWidget* parent = nullptr);
+    explicit GraphicsSurfaceWidget(std::shared_ptr<Pica::DebugContext> debug_context,
+                                   QWidget* parent = nullptr);
     void Pick(int x, int y);
 
 public slots:
diff --git a/src/citra_qt/debugger/graphics_tracing.h b/src/citra_qt/debugger/graphics_tracing.h
index e04a3dac3..20acc91e7 100644
--- a/src/citra_qt/debugger/graphics_tracing.h
+++ b/src/citra_qt/debugger/graphics_tracing.h
@@ -12,8 +12,8 @@ class GraphicsTracingWidget : public BreakPointObserverDock {
     Q_OBJECT
 
 public:
-    GraphicsTracingWidget(std::shared_ptr<Pica::DebugContext> debug_context,
-                          QWidget* parent = nullptr);
+    explicit GraphicsTracingWidget(std::shared_ptr<Pica::DebugContext> debug_context,
+                                   QWidget* parent = nullptr);
 
 private slots:
     void StartRecording();
diff --git a/src/citra_qt/debugger/graphics_vertex_shader.h b/src/citra_qt/debugger/graphics_vertex_shader.h
index ec42f24bb..6e62fbb9b 100644
--- a/src/citra_qt/debugger/graphics_vertex_shader.h
+++ b/src/citra_qt/debugger/graphics_vertex_shader.h
@@ -19,7 +19,7 @@ class GraphicsVertexShaderModel : public QAbstractTableModel {
     Q_OBJECT
 
 public:
-    GraphicsVertexShaderModel(GraphicsVertexShaderWidget* parent);
+    explicit GraphicsVertexShaderModel(GraphicsVertexShaderWidget* parent);
 
     int columnCount(const QModelIndex& parent = QModelIndex()) const override;
     int rowCount(const QModelIndex& parent = QModelIndex()) const override;
diff --git a/src/citra_qt/debugger/profiler.h b/src/citra_qt/debugger/profiler.h
index d8c6487aa..c8912fd5a 100644
--- a/src/citra_qt/debugger/profiler.h
+++ b/src/citra_qt/debugger/profiler.h
@@ -15,7 +15,7 @@ class ProfilerModel : public QAbstractItemModel {
     Q_OBJECT
 
 public:
-    ProfilerModel(QObject* parent);
+    explicit ProfilerModel(QObject* parent);
 
     QVariant headerData(int section, Qt::Orientation orientation,
                         int role = Qt::DisplayRole) const override;
@@ -37,7 +37,7 @@ class ProfilerWidget : public QDockWidget {
     Q_OBJECT
 
 public:
-    ProfilerWidget(QWidget* parent = nullptr);
+    explicit ProfilerWidget(QWidget* parent = nullptr);
 
 private slots:
     void setProfilingInfoUpdateEnabled(bool enable);
@@ -53,7 +53,7 @@ class MicroProfileDialog : public QWidget {
     Q_OBJECT
 
 public:
-    MicroProfileDialog(QWidget* parent = nullptr);
+    explicit MicroProfileDialog(QWidget* parent = nullptr);
 
     /// Returns a QAction that can be used to toggle visibility of this dialog.
     QAction* toggleViewAction();
diff --git a/src/citra_qt/debugger/ramview.h b/src/citra_qt/debugger/ramview.h
index 993345eec..d01cea93b 100644
--- a/src/citra_qt/debugger/ramview.h
+++ b/src/citra_qt/debugger/ramview.h
@@ -10,7 +10,7 @@ class GRamView : public QHexEdit {
     Q_OBJECT
 
 public:
-    GRamView(QWidget* parent = nullptr);
+    explicit GRamView(QWidget* parent = nullptr);
 
 public slots:
     void OnCPUStepped();
diff --git a/src/citra_qt/debugger/registers.h b/src/citra_qt/debugger/registers.h
index 8e349bd73..55bda5b59 100644
--- a/src/citra_qt/debugger/registers.h
+++ b/src/citra_qt/debugger/registers.h
@@ -15,7 +15,7 @@ class RegistersWidget : public QDockWidget {
     Q_OBJECT
 
 public:
-    RegistersWidget(QWidget* parent = nullptr);
+    explicit RegistersWidget(QWidget* parent = nullptr);
 
 public slots:
     void OnDebugModeEntered();
diff --git a/src/citra_qt/debugger/wait_tree.h b/src/citra_qt/debugger/wait_tree.h
index 1af73b963..ee9708fc1 100644
--- a/src/citra_qt/debugger/wait_tree.h
+++ b/src/citra_qt/debugger/wait_tree.h
@@ -51,7 +51,7 @@ private:
 class WaitTreeText : public WaitTreeItem {
     Q_OBJECT
 public:
-    WaitTreeText(const QString& text);
+    explicit WaitTreeText(const QString& text);
     QString GetText() const override;
 
 private:
@@ -67,7 +67,7 @@ public:
 class WaitTreeWaitObject : public WaitTreeExpandableItem {
     Q_OBJECT
 public:
-    WaitTreeWaitObject(const Kernel::WaitObject& object);
+    explicit WaitTreeWaitObject(const Kernel::WaitObject& object);
     static std::unique_ptr<WaitTreeWaitObject> make(const Kernel::WaitObject& object);
     QString GetText() const override;
     std::vector<std::unique_ptr<WaitTreeItem>> GetChildren() const override;
@@ -94,7 +94,7 @@ private:
 class WaitTreeThread : public WaitTreeWaitObject {
     Q_OBJECT
 public:
-    WaitTreeThread(const Kernel::Thread& thread);
+    explicit WaitTreeThread(const Kernel::Thread& thread);
     QString GetText() const override;
     QColor GetColor() const override;
     std::vector<std::unique_ptr<WaitTreeItem>> GetChildren() const override;
@@ -103,35 +103,37 @@ public:
 class WaitTreeEvent : public WaitTreeWaitObject {
     Q_OBJECT
 public:
-    WaitTreeEvent(const Kernel::Event& object);
+    explicit WaitTreeEvent(const Kernel::Event& object);
     std::vector<std::unique_ptr<WaitTreeItem>> GetChildren() const override;
 };
 
 class WaitTreeMutex : public WaitTreeWaitObject {
     Q_OBJECT
 public:
-    WaitTreeMutex(const Kernel::Mutex& object);
+    explicit WaitTreeMutex(const Kernel::Mutex& object);
     std::vector<std::unique_ptr<WaitTreeItem>> GetChildren() const override;
 };
 
 class WaitTreeSemaphore : public WaitTreeWaitObject {
     Q_OBJECT
 public:
-    WaitTreeSemaphore(const Kernel::Semaphore& object);
+    explicit WaitTreeSemaphore(const Kernel::Semaphore& object);
     std::vector<std::unique_ptr<WaitTreeItem>> GetChildren() const override;
 };
 
 class WaitTreeTimer : public WaitTreeWaitObject {
     Q_OBJECT
 public:
-    WaitTreeTimer(const Kernel::Timer& object);
+    explicit WaitTreeTimer(const Kernel::Timer& object);
     std::vector<std::unique_ptr<WaitTreeItem>> GetChildren() const override;
 };
 
 class WaitTreeMutexList : public WaitTreeExpandableItem {
     Q_OBJECT
 public:
-    WaitTreeMutexList(const boost::container::flat_set<Kernel::SharedPtr<Kernel::Mutex>>& list);
+    explicit WaitTreeMutexList(
+        const boost::container::flat_set<Kernel::SharedPtr<Kernel::Mutex>>& list);
+
     QString GetText() const override;
     std::vector<std::unique_ptr<WaitTreeItem>> GetChildren() const override;
 
@@ -142,7 +144,7 @@ private:
 class WaitTreeThreadList : public WaitTreeExpandableItem {
     Q_OBJECT
 public:
-    WaitTreeThreadList(const std::vector<Kernel::SharedPtr<Kernel::Thread>>& list);
+    explicit WaitTreeThreadList(const std::vector<Kernel::SharedPtr<Kernel::Thread>>& list);
     QString GetText() const override;
     std::vector<std::unique_ptr<WaitTreeItem>> GetChildren() const override;
 
@@ -154,7 +156,7 @@ class WaitTreeModel : public QAbstractItemModel {
     Q_OBJECT
 
 public:
-    WaitTreeModel(QObject* parent = nullptr);
+    explicit WaitTreeModel(QObject* parent = nullptr);
 
     QVariant data(const QModelIndex& index, int role) const override;
     QModelIndex index(int row, int column, const QModelIndex& parent) const override;
@@ -173,7 +175,7 @@ class WaitTreeWidget : public QDockWidget {
     Q_OBJECT
 
 public:
-    WaitTreeWidget(QWidget* parent = nullptr);
+    explicit WaitTreeWidget(QWidget* parent = nullptr);
 
 public slots:
     void OnDebugModeEntered();
diff --git a/src/citra_qt/hotkeys.h b/src/citra_qt/hotkeys.h
index 350103c6f..46f48c2d8 100644
--- a/src/citra_qt/hotkeys.h
+++ b/src/citra_qt/hotkeys.h
@@ -55,7 +55,7 @@ class GHotkeysDialog : public QWidget {
     Q_OBJECT
 
 public:
-    GHotkeysDialog(QWidget* parent = nullptr);
+    explicit GHotkeysDialog(QWidget* parent = nullptr);
 
 private:
     Ui::hotkeys ui;
diff --git a/src/citra_qt/util/spinbox.h b/src/citra_qt/util/spinbox.h
index a57355cd6..2fa1db3a4 100644
--- a/src/citra_qt/util/spinbox.h
+++ b/src/citra_qt/util/spinbox.h
@@ -42,7 +42,7 @@ class CSpinBox : public QAbstractSpinBox {
     Q_OBJECT
 
 public:
-    CSpinBox(QWidget* parent = nullptr);
+    explicit CSpinBox(QWidget* parent = nullptr);
 
     void stepBy(int steps) override;
     StepEnabled stepEnabled() const override;