diff --git a/pandas/core/generic.py b/pandas/core/generic.py
index fe412bc0ce937..c3c4a14146541 100644
--- a/pandas/core/generic.py
+++ b/pandas/core/generic.py
@@ -2063,6 +2063,7 @@ def to_json(
         index: bool_t = True,
         indent: Optional[int] = None,
         storage_options: StorageOptions = None,
+        mode: str = "w",
     ) -> Optional[str]:
         """
         Convert the object to a JSON string.
@@ -2156,6 +2157,13 @@ def to_json(
 
             .. versionadded:: 1.2.0
 
+        mode : str, default 'w'
+            If 'orient' is 'records' and 'lines' is 'True' enable option to append
+            mode ('mode' is 'a') to a json file instead of overwriting.
+            Will throw ValueError if incorrect 'orient' and 'lines'.
+
+           .. versionadded:: 1.2.0
+
         Returns
         -------
         None or str
@@ -2335,6 +2343,7 @@ def to_json(
             index=index,
             indent=indent,
             storage_options=storage_options,
+            mode=mode,
         )
 
     def to_hdf(
diff --git a/pandas/io/json/_json.py b/pandas/io/json/_json.py
index fe5e172655ae1..627b8a48100a8 100644
--- a/pandas/io/json/_json.py
+++ b/pandas/io/json/_json.py
@@ -50,6 +50,7 @@ def to_json(
     index: bool = True,
     indent: int = 0,
     storage_options: StorageOptions = None,
+    mode: str = "w",
 ):
 
     if not index and orient not in ["split", "table"]:
@@ -68,6 +69,11 @@ def to_json(
     if lines and orient != "records":
         raise ValueError("'lines' keyword only valid when 'orient' is records")
 
+    if mode == "a" and (not lines or orient != "records"):
+        raise ValueError(
+            "'append mode' only valid when 'line' is True and 'orient' is records"
+        )
+
     if orient == "table" and isinstance(obj, Series):
         obj = obj.to_frame(name=obj.name or "values")
 
@@ -95,9 +101,19 @@ def to_json(
 
     if lines:
         s = convert_to_line_delimits(s)
+        try:
+            add_new_line = (
+                mode == "a"
+                and os.path.exists(path_or_buf)
+                and os.path.isfile(path_or_buf)
+                and os.path.getsize(path_or_buf)
+            )
+            s = "\n" + s if add_new_line else s
+        except (TypeError, ValueError):
+            pass
 
     if isinstance(path_or_buf, str):
-        fh, handles = get_handle(path_or_buf, "w", compression=compression)
+        fh, handles = get_handle(path_or_buf, mode, compression=compression)
         try:
             fh.write(s)
         finally: