diff --git a/src/Conn.h b/src/Conn.h
index a2bb1face5..4211520525 100644
--- a/src/Conn.h
+++ b/src/Conn.h
@@ -379,7 +379,7 @@ protected:
 	WeirdStateMap weird_state;
 };
 
-class ConnectionTimer : public Timer {
+class ConnectionTimer final : public Timer {
 public:
 	ConnectionTimer(Connection* arg_conn, timer_func arg_timer,
 			double arg_t, bool arg_do_expire, TimerType arg_type)
diff --git a/src/DbgBreakpoint.cc b/src/DbgBreakpoint.cc
index 7bd18ce05f..aeb9ed0487 100644
--- a/src/DbgBreakpoint.cc
+++ b/src/DbgBreakpoint.cc
@@ -21,7 +21,7 @@
 #include "module_util.h"
 
 // BreakpointTimer used for time-based breakpoints
-class BreakpointTimer : public Timer {
+class BreakpointTimer final : public Timer {
 public:
 	BreakpointTimer(DbgBreakpoint* arg_bp, double arg_t)
 		: Timer(arg_t, TIMER_BREAKPOINT)
diff --git a/src/Expr.h b/src/Expr.h
index 1ed01a57a9..8013d8129a 100644
--- a/src/Expr.h
+++ b/src/Expr.h
@@ -740,7 +740,7 @@ protected:
 	int num_fields;
 };
 
-class ScheduleTimer : public Timer {
+class ScheduleTimer final : public Timer {
 public:
 	ScheduleTimer(const EventHandlerPtr& event, zeek::Args args, double t);
 	~ScheduleTimer() override;
diff --git a/src/Frag.h b/src/Frag.h
index 31d5ec5bd0..5dc9f06bc7 100644
--- a/src/Frag.h
+++ b/src/Frag.h
@@ -53,7 +53,7 @@ protected:
 	FragTimer* expire_timer;
 };
 
-class FragTimer : public Timer {
+class FragTimer final : public Timer {
 public:
 	FragTimer(FragReassembler* arg_f, double arg_t)
 		: Timer(arg_t, TIMER_FRAG)
diff --git a/src/Reporter.cc b/src/Reporter.cc
index 68446dd553..df48205d05 100644
--- a/src/Reporter.cc
+++ b/src/Reporter.cc
@@ -238,7 +238,7 @@ void Reporter::UpdateWeirdStats(const char* name)
 	++weird_count_by_type[name];
 	}
 
-class NetWeirdTimer : public Timer {
+class NetWeirdTimer final : public Timer {
 public:
 	NetWeirdTimer(double t, const char* name, double timeout)
 	: Timer(t + timeout, TIMER_NET_WEIRD_EXPIRE), weird_name(name)
@@ -250,7 +250,7 @@ public:
 	std::string weird_name;
 };
 
-class FlowWeirdTimer : public Timer {
+class FlowWeirdTimer final : public Timer {
 public:
 	using IPPair = std::pair<IPAddr, IPAddr>;
 
diff --git a/src/Sessions.h b/src/Sessions.h
index efa4e430a2..33b9ee02f8 100644
--- a/src/Sessions.h
+++ b/src/Sessions.h
@@ -237,7 +237,7 @@ protected:
 };
 
 
-class IPTunnelTimer : public Timer {
+class IPTunnelTimer final : public Timer {
 public:
 	IPTunnelTimer(double t, NetSessions::IPPair p)
 	: Timer(t + BifConst::Tunnel::ip_tunnel_timeout,
diff --git a/src/Stats.cc b/src/Stats.cc
index 8720933fae..d05f82950e 100644
--- a/src/Stats.cc
+++ b/src/Stats.cc
@@ -22,7 +22,7 @@ uint64_t tot_gap_events = 0;
 uint64_t tot_gap_bytes = 0;
 
 
-class ProfileTimer : public Timer {
+class ProfileTimer final : public Timer {
 public:
 	ProfileTimer(double t, ProfileLogger* l, double i)
 	: Timer(t, TIMER_PROFILE)
diff --git a/src/Trigger.cc b/src/Trigger.cc
index d3b11e5cd8..20cce502c5 100644
--- a/src/Trigger.cc
+++ b/src/Trigger.cc
@@ -84,7 +84,7 @@ TraversalCode TriggerTraversalCallback::PreExpr(const Expr* expr)
 
 namespace trigger {
 
-class TriggerTimer : public Timer {
+class TriggerTimer final : public Timer {
 public:
 	TriggerTimer(double arg_timeout, Trigger* arg_trigger)
 	: Timer(network_time + arg_timeout, TIMER_TRIGGER)
diff --git a/src/Val.h b/src/Val.h
index 96b610892d..c8c19bdb45 100644
--- a/src/Val.h
+++ b/src/Val.h
@@ -674,7 +674,7 @@ protected:
 	int expire_access_time;
 };
 
-class TableValTimer : public Timer {
+class TableValTimer final : public Timer {
 public:
 	TableValTimer(TableVal* val, double t);
 	~TableValTimer() override;
diff --git a/src/analyzer/Analyzer.cc b/src/analyzer/Analyzer.cc
index 6f109c4b72..57c74a4a2a 100644
--- a/src/analyzer/Analyzer.cc
+++ b/src/analyzer/Analyzer.cc
@@ -12,7 +12,7 @@
 
 namespace analyzer {
 
-class AnalyzerTimer : public Timer {
+class AnalyzerTimer final : public Timer {
 public:
 	AnalyzerTimer(Analyzer* arg_analyzer, analyzer_timer_func arg_timer,
 			double arg_t, int arg_do_expire, TimerType arg_type);
diff --git a/src/file_analysis/FileTimer.h b/src/file_analysis/FileTimer.h
index 605fc2b8a8..4664b904bb 100644
--- a/src/file_analysis/FileTimer.h
+++ b/src/file_analysis/FileTimer.h
@@ -13,7 +13,7 @@ namespace file_analysis {
 /**
  * Timer to periodically check if file analysis for a given file is inactive.
  */
-class FileTimer : public Timer {
+class FileTimer final : public Timer {
 public:
 
 	/**
diff --git a/src/logging/Manager.cc b/src/logging/Manager.cc
index d1af7e674c..0ed09bbbeb 100644
--- a/src/logging/Manager.cc
+++ b/src/logging/Manager.cc
@@ -1390,7 +1390,7 @@ RecordType* Manager::StreamColumns(EnumVal* stream_id)
 	}
 
 // Timer which on dispatching rotates the filter.
-class RotationTimer : public Timer {
+class RotationTimer final : public Timer {
 public:
 	RotationTimer(double t, Manager::WriterInfo* arg_winfo, bool arg_rotate)
 		: Timer(t, TIMER_ROTATE)
diff --git a/src/supervisor/Supervisor.h b/src/supervisor/Supervisor.h
index d7de0d0c2b..b38c1ad072 100644
--- a/src/supervisor/Supervisor.h
+++ b/src/supervisor/Supervisor.h
@@ -394,7 +394,7 @@ private:
  * parent (supervisor) process has died.  If it has died, the supervised
  * process self-terminates.
  */
-class ParentProcessCheckTimer : public Timer {
+class ParentProcessCheckTimer final : public Timer {
 public:
 
 	/**
diff --git a/src/threading/Manager.h b/src/threading/Manager.h
index 146420aca6..3285b8e4b6 100644
--- a/src/threading/Manager.h
+++ b/src/threading/Manager.h
@@ -9,7 +9,7 @@
 
 namespace threading {
 
-class HeartbeatTimer : public Timer {
+class HeartbeatTimer final : public Timer {
 public:
 	HeartbeatTimer(double t) : Timer(t, TIMER_THREAD_HEARTBEAT) {}
 	virtual ~HeartbeatTimer() {}