diff --git a/src/Concelier/__Libraries/StellaOps.Concelier.Core/Jobs/JobCoordinator.cs b/src/Concelier/__Libraries/StellaOps.Concelier.Core/Jobs/JobCoordinator.cs
index e3ba7f1f2..be6df50c2 100644
--- a/src/Concelier/__Libraries/StellaOps.Concelier.Core/Jobs/JobCoordinator.cs
+++ b/src/Concelier/__Libraries/StellaOps.Concelier.Core/Jobs/JobCoordinator.cs
@@ -22,6 +22,7 @@ public sealed class JobCoordinator : IJobCoordinator
     private readonly TimeProvider _timeProvider;
     private readonly JobDiagnostics _diagnostics;
     private readonly string _holderId;
+    private readonly SemaphoreSlim _concurrencyGate;
 
     public JobCoordinator(
         IOptions<JobSchedulerOptions> optionsAccessor,
@@ -42,6 +43,7 @@ public sealed class JobCoordinator : IJobCoordinator
         _timeProvider = timeProvider ?? throw new ArgumentNullException(nameof(timeProvider));
         _diagnostics = diagnostics ?? throw new ArgumentNullException(nameof(diagnostics));
         _holderId = BuildHolderId();
+        _concurrencyGate = new SemaphoreSlim(_options.MaxConcurrentJobs, _options.MaxConcurrentJobs);
     }
 
     public async Task<JobTriggerResult> TriggerAsync(string kind, IReadOnlyDictionary<string, object?>? parameters, string trigger, CancellationToken cancellationToken)
@@ -437,6 +439,27 @@ public sealed class JobCoordinator : IJobCoordinator
         IReadOnlyDictionary<string, object?> parameters,
         string trigger,
         CancellationTokenSource linkedTokenSource)
+    {
+        // Limit concurrent job execution to prevent resource exhaustion (DB connections, HTTP, CPU).
+        // The semaphore is bounded by MaxConcurrentJobs (default: 6).
+        await _concurrencyGate.WaitAsync(linkedTokenSource.Token).ConfigureAwait(false);
+        try
+        {
+        await ExecuteJobCoreAsync(definition, lease, run, parameters, trigger, linkedTokenSource).ConfigureAwait(false);
+        }
+        finally
+        {
+            _concurrencyGate.Release();
+        }
+    }
+
+    private async Task ExecuteJobCoreAsync(
+        JobDefinition definition,
+        JobLease lease,
+        JobRunSnapshot run,
+        IReadOnlyDictionary<string, object?> parameters,
+        string trigger,
+        CancellationTokenSource linkedTokenSource)
     {
         using (linkedTokenSource)
         {
diff --git a/src/Concelier/__Libraries/StellaOps.Concelier.Core/Jobs/JobSchedulerOptions.cs b/src/Concelier/__Libraries/StellaOps.Concelier.Core/Jobs/JobSchedulerOptions.cs
index b5db137af..383701b9b 100644
--- a/src/Concelier/__Libraries/StellaOps.Concelier.Core/Jobs/JobSchedulerOptions.cs
+++ b/src/Concelier/__Libraries/StellaOps.Concelier.Core/Jobs/JobSchedulerOptions.cs
@@ -9,4 +9,11 @@ public sealed class JobSchedulerOptions
     public TimeSpan DefaultTimeout { get; set; } = TimeSpan.FromMinutes(15);
 
     public TimeSpan DefaultLeaseDuration { get; set; } = TimeSpan.FromMinutes(5);
+
+    /// <summary>
+    /// Maximum number of jobs that can execute concurrently.
+    /// When exceeded, new triggers will queue behind the semaphore.
+    /// Default: 6 (balances throughput vs. resource pressure).
+    /// </summary>
+    public int MaxConcurrentJobs { get; set; } = 6;
 }