diff --git a/Shell/LineEditor.cpp b/Shell/LineEditor.cpp
index 5e36ca16c5..ebfaf10150 100644
--- a/Shell/LineEditor.cpp
+++ b/Shell/LineEditor.cpp
@@ -37,6 +37,60 @@ void LineEditor::append(const String& string)
     m_cursor = m_buffer.size();
 }
 
+void LineEditor::tab_complete_first_token()
+{
+    auto input = String::copy(m_buffer);
+
+    String path = getenv("PATH");
+    if (path.is_empty())
+        return;
+    auto directories = path.split(':');
+
+    String match;
+
+    // Go through the files in PATH.
+    for (const auto& directory : directories) {
+        CDirIterator programs(directory.characters(), CDirIterator::SkipDots);
+        while (programs.has_next()) {
+            String program = programs.next_path();
+            if (!program.starts_with(input))
+                continue;
+
+            // Check that the file is an executable program.
+            struct stat program_status;
+            StringBuilder program_path;
+            program_path.append(directory.characters());
+            program_path.append('/');
+            program_path.append(program.characters());
+            int stat_error = stat(program_path.to_string().characters(), &program_status);
+            if (stat_error || !(program_status.st_mode & S_IXUSR))
+                continue;
+
+            // Set `match` to the first one that starts with `input`.
+            if (match.is_empty()) {
+                match = program;
+            } else {
+                // Remove characters from the end of `match` if they're
+                // different from another `program` starting with `input`.
+                int i = input.length();
+                while (i < match.length() && i < program.length() && match[i] == program[i])
+                    ++i;
+                match = match.substring(0, i);
+            }
+
+            if (match.length() == input.length())
+                return;
+        }
+    }
+
+    if (match.is_empty())
+        return;
+
+    // Then append `match` to the buffer, excluding the `input` part which is
+    // already in the buffer.
+    append(match.substring(input.length(), match.length() - input.length()).characters());
+}
+
 String LineEditor::get_line(const String& prompt)
 {
     fputs(prompt.characters(), stdout);
@@ -174,7 +228,21 @@ String LineEditor::get_line(const String& prompt)
             }
 
             if (ch == '\t') {
-                // FIXME: Implement tab-completion.
+                if (m_buffer.is_empty())
+                    continue;
+
+                bool is_first_token = true;
+                for (const auto& character : m_buffer) {
+                    if (isspace(character)) {
+                        is_first_token = false;
+                        break;
+                    }
+                }
+
+                // FIXME: Implement tab-completion for other tokens (paths).
+                if (is_first_token)
+                    tab_complete_first_token();
+
                 continue;
             }
 
diff --git a/Shell/LineEditor.h b/Shell/LineEditor.h
index 5f5a4344d7..b2a5b1c6dc 100644
--- a/Shell/LineEditor.h
+++ b/Shell/LineEditor.h
@@ -1,7 +1,10 @@
 #pragma once
 
 #include <AK/String.h>
+#include <AK/StringBuilder.h>
 #include <AK/Vector.h>
+#include <LibCore/CDirIterator.h>
+#include <sys/stat.h>
 
 class LineEditor {
 public:
@@ -16,6 +19,7 @@ public:
 private:
     void clear_line();
     void append(const String&);
+    void tab_complete_first_token();
     void vt_save_cursor();
     void vt_restore_cursor();
     void vt_clear_to_end_of_line();