diff --git a/src/cascadia/TerminalApp/CommandPalette.cpp b/src/cascadia/TerminalApp/CommandPalette.cpp
index be16f2f1b..a4b4c0b8f 100644
--- a/src/cascadia/TerminalApp/CommandPalette.cpp
+++ b/src/cascadia/TerminalApp/CommandPalette.cpp
@@ -1275,15 +1275,39 @@ namespace winrt::TerminalApp::implementation
     void CommandPalette::_updateRecentCommands(const hstring& command)
     {
         const auto recentCommands = ApplicationState::SharedInstance().RecentCommands();
-        // If there aren't and recent commands already in the state, then we
-        // don't need to copy any.
-        const auto countToCopy = std::min(recentCommands ? recentCommands.Size() : 0, CommandLineHistoryLength - 1);
-        std::vector<hstring> newRecentCommands{ countToCopy + 1 };
-        til::at(newRecentCommands, 0) = command;
-        if (countToCopy)
+        // If this is the first time we've opened the commandline mode and
+        // there aren't any recent commands, then just store the new command.
+        if (!recentCommands)
         {
-            recentCommands.GetMany(0, { newRecentCommands.data() + 1, countToCopy });
+            ApplicationState::SharedInstance().RecentCommands(single_threaded_vector(std::move(std::vector{ command })));
+            return;
         }
+
+        const auto numNewRecentCommands = std::min(recentCommands.Size() + 1, CommandLineHistoryLength);
+
+        std::vector<hstring> newRecentCommands;
+        newRecentCommands.reserve(numNewRecentCommands);
+
+        std::unordered_set<hstring> uniqueCommands;
+        uniqueCommands.reserve(numNewRecentCommands);
+
+        newRecentCommands.push_back(command);
+        uniqueCommands.insert(command);
+
+        for (const auto& c : recentCommands)
+        {
+            if (newRecentCommands.size() >= CommandLineHistoryLength)
+            {
+                // Don't store more than CommandLineHistoryLength commands
+                break;
+            }
+
+            if (uniqueCommands.emplace(c).second)
+            {
+                newRecentCommands.push_back(c);
+            }
+        }
+
         ApplicationState::SharedInstance().RecentCommands(single_threaded_vector(std::move(newRecentCommands)));
     }
 }