diff --git a/pandas/core/strings.py b/pandas/core/strings.py
index bd756491abd2f..79d940182912a 100644
--- a/pandas/core/strings.py
+++ b/pandas/core/strings.py
@@ -999,23 +999,21 @@ def str_get_dummies(arr, sep='|'):
     1  0  0  0
     2  1  0  1
     """
-    arr = arr.fillna('')
-    try:
-        arr = sep + arr + sep
-    except TypeError:
-        arr = sep + arr.astype(str) + sep
+    from pandas.core.reshape.reshape import get_dummies
+    from pandas import Series
+
+    arr = arr.fillna('').astype('str')
+
+    arr_split = arr.str.split(sep)
 
-    tags = set()
-    for ts in arr.str.split(sep):
-        tags.update(ts)
-    tags = sorted(tags - {""})
+    stacked = Series(np.concatenate(arr_split)) if len(arr) > 0 else Series()
+    stacked[stacked == ''] = np.nan
+    stacked_idx = np.repeat(np.arange(len(arr)), arr_split.str.len())
 
-    dummies = np.empty((len(arr), len(tags)), dtype=np.int64)
+    dummies_stacked = get_dummies(stacked)
+    dummies = dummies_stacked.groupby(by=stacked_idx).sum()
 
-    for i, t in enumerate(tags):
-        pat = sep + t + sep
-        dummies[:, i] = lib.map_infer(arr.values, lambda x: pat in x)
-    return dummies, tags
+    return dummies.values, dummies.columns.values
 
 
 def str_join(arr, sep):