diff --git a/Orange/projection/manifold.py b/Orange/projection/manifold.py
index f67874e59b0..5e7cbcd12c8 100644
--- a/Orange/projection/manifold.py
+++ b/Orange/projection/manifold.py
@@ -8,10 +8,6 @@
 from scipy.sparse.linalg import eigsh as arpack_eigh
 import sklearn.manifold as skl_manifold
 
-import openTSNE
-import openTSNE.affinity
-import openTSNE.initialization
-
 import Orange
 from Orange.data import Table, Domain, ContinuousVariable
 from Orange.distance import Distance, DistanceModel, Euclidean
@@ -21,10 +17,6 @@
 __all__ = ["MDS", "Isomap", "LocallyLinearEmbedding", "SpectralEmbedding",
            "TSNE"]
 
-# Disable t-SNE user warnings
-openTSNE.tsne.log.setLevel(logging.ERROR)
-openTSNE.affinity.log.setLevel(logging.ERROR)
-
 
 def torgerson(distances, n_components=2, eigen_solver="auto"):
     """
@@ -190,6 +182,23 @@ def __init__(self, n_components=2, affinity='nearest_neighbors', gamma=None,
         self.params = vars()
 
 
+class lazy_openTSNE:
+    """openTSNE uses numba, which is slow to load, so load it lazily."""
+    def __getattr__(self, item):
+        import sys
+        import openTSNE
+        import openTSNE.affinity
+        import openTSNE.initialization
+        if "openTSNE" in sys.modules:
+            # Disable t-SNE user warnings
+            openTSNE.tsne.log.setLevel(logging.ERROR)
+            openTSNE.affinity.log.setLevel(logging.ERROR)
+        return getattr(openTSNE, item)
+
+
+openTSNE = lazy_openTSNE()
+
+
 class TSNEModel(Projection):
     """A t-SNE embedding object. Supports further optimization as well as
     adding new data into the existing embedding.
@@ -204,8 +213,8 @@ class TSNEModel(Projection):
     pre_domain : Domain
         Original data domain
     """
-    def __init__(self, embedding: openTSNE.TSNEEmbedding, table: Table,
-                 pre_domain: Domain):
+    def __init__(self, embedding, table, pre_domain):
+        # type: (openTSNE.TSNEEmbedding, Table, Domain) -> None
         transformer = TransformDomain(self)
 
         def proj_variable(i):
@@ -221,7 +230,8 @@ def proj_variable(i):
             class_vars=table.domain.class_vars,
             metas=table.domain.metas)
 
-    def transform(self, X: np.ndarray, learning_rate=1, **kwargs) -> openTSNE.PartialTSNEEmbedding:
+    def transform(self, X, learning_rate=1, **kwargs):
+        # type: (np.ndarray, int, ...) -> openTSNE.PartialTSNEEmbedding
         if sp.issparse(X):
             raise TypeError(
                 "A sparse matrix was passed, but dense data is required. Use "
@@ -481,7 +491,8 @@ def prepare_embedding(self, affinities, initialization):
             callbacks_every_iters=self.callbacks_every_iters,
         )
 
-    def fit(self, X: np.ndarray, Y: np.ndarray = None) -> openTSNE.TSNEEmbedding:
+    def fit(self, X, Y=None):
+        # type: (np.ndarray, Optional[np.ndarray]) -> openTSNE.TSNEEmbedding
         # Compute affinities and initial positions and prepare the embedding object
         affinities = self.compute_affinities(X)
         initialization = self.compute_initialization(X)