diff --git a/pyoptsparse/__init__.py b/pyoptsparse/__init__.py
index e19a0e7f..903a0881 100644
--- a/pyoptsparse/__init__.py
+++ b/pyoptsparse/__init__.py
@@ -19,3 +19,25 @@
 from .pyNSGA2.pyNSGA2 import NSGA2
 from .pyALPSO.pyALPSO import ALPSO
 from .pyParOpt.ParOpt import ParOpt
+
+__all__ = [
+    "History",
+    "Variable",
+    "Gradient",
+    "Constraint",
+    "Objective",
+    "Optimization",
+    "Optimizer",
+    "OPT",
+    "Optimizers",
+    "Solution",
+    "SNOPT",
+    "IPOPT",
+    "SLSQP",
+    "CONMIN",
+    "PSQP",
+    "NLPQLP",
+    "NSGA2",
+    "ALPSO",
+    "ParOpt",
+]