diff --git a/common/CMakeLists.txt b/common/CMakeLists.txt
index 69eab22f4..b484af16e 100644
--- a/common/CMakeLists.txt
+++ b/common/CMakeLists.txt
@@ -43,6 +43,9 @@ ADD_LIBRARY(JFJochLogger STATIC
 )
 
 TARGET_LINK_LIBRARIES(JFJochLogger PUBLIC spdlog::spdlog JFJochVersion)
+IF (JFJOCH_CUDA_AVAILABLE)
+    TARGET_LINK_LIBRARIES(JFJochLogger PRIVATE CUDA::nvtx3)   # header-only NVTX v3
+ENDIF()
 
 ADD_LIBRARY(JFJochZMQ STATIC ZMQWrappers.cpp ZMQWrappers.h)
 
diff --git a/common/Logger.cpp b/common/Logger.cpp
index de61bedff..f84d357db 100644
--- a/common/Logger.cpp
+++ b/common/Logger.cpp
@@ -9,6 +9,24 @@
 #include "Logger.h"
 #include "GitInfo.h"
 
+#ifdef JFJOCH_USE_CUDA
+#include <nvtx3/nvToolsExt.h>
+
+uint64_t NvtxRangeStart(const std::string &name) {
+    return nvtxRangeStartA(name.c_str());
+}
+
+void NvtxRangeEnd(uint64_t id) {
+    nvtxRangeEnd(id);
+}
+#else
+uint64_t NvtxRangeStart(const std::string &) {
+    return 0;
+}
+
+void NvtxRangeEnd(uint64_t) {}
+#endif
+
 namespace {
     spdlog::sink_ptr routed_sink;   // set once, at start-up, before any thread logs
 }
diff --git a/common/Logger.h b/common/Logger.h
index 57795ec55..4549aeb4c 100644
--- a/common/Logger.h
+++ b/common/Logger.h
@@ -70,13 +70,21 @@ public:
     void ReplayInto(Logger &to) const;
 };
 
+// An NVTX range named `name`, so a timed section shows up by name in an Nsight Systems trace. A start/end
+// pair, not a push/pop, so a range may end on another thread and ranges on parallel threads may overlap.
+// Without a profiler attached both calls return at once; without CUDA they do nothing.
+uint64_t NvtxRangeStart(const std::string &name);
+void NvtxRangeEnd(uint64_t id);
+
 // Times one section of a run: logs "TIMING <section> <seconds>" at debug level when the section ends -
 // at Stop(), or when the mark goes out of scope, whichever comes first. rugnux keeps debug lines off the
-// terminal and in <prefix>_log.txt; tools/rugnux_timing.py turns them into a table.
+// terminal and in <prefix>_log.txt; tools/rugnux_timing.py turns them into a table. The section is also
+// an NVTX range of the same name.
 class TimingMark {
     Logger &logger;
     std::string section;
     std::chrono::steady_clock::time_point start = std::chrono::steady_clock::now();
+    uint64_t nvtx_range = NvtxRangeStart(section);
     bool stopped = false;
 public:
     TimingMark(Logger &in_logger, std::string in_section)
@@ -88,6 +96,7 @@ public:
         if (stopped)
             return;
         stopped = true;
+        NvtxRangeEnd(nvtx_range);
         logger.Debug("TIMING {} {:.3f}", section,
                      std::chrono::duration<double>(std::chrono::steady_clock::now() - start).count());
     }
diff --git a/rugnux/RugnuxConsole.cpp b/rugnux/RugnuxConsole.cpp
index 0d74e4f35..12c1a0e36 100644
--- a/rugnux/RugnuxConsole.cpp
+++ b/rugnux/RugnuxConsole.cpp
@@ -204,6 +204,7 @@ void RugnuxConsole::Close(const char *how) {
     }
     pending_log_.push_back(std::move(log_text));
     pending_timing_.push_back(fmt::format("TIMING step {} {:.3f}", step_title_, total));
+    NvtxRangeEnd(step_nvtx_);
     warnings_held_.clear();
     step_ = 0;
 }
@@ -216,6 +217,7 @@ void RugnuxConsole::OnStep(const std::string &title) {
         step_ = last_step_ = number;
         step_title_ = title;
         step_start_ = mark_ = Clock::now();
+        step_nvtx_ = NvtxRangeStart(fmt::format("Step {} {}", step_, title));
         notes_ = 0;
         if (!verbose_)
             Emit(fmt::format("Step {:<2} {}", step_, title));
diff --git a/rugnux/RugnuxConsole.h b/rugnux/RugnuxConsole.h
index 5d91e5f81..fb12eb021 100644
--- a/rugnux/RugnuxConsole.h
+++ b/rugnux/RugnuxConsole.h
@@ -74,6 +74,7 @@ private:
     int last_step_ = 0;
     std::string step_title_;
     Clock::time_point step_start_{};
+    uint64_t step_nvtx_ = 0;       // the open step's NVTX range
     Clock::time_point mark_{};     // the last line of the open step
     int notes_ = 0;