diff --git a/README.md b/README.md
index 844245a..c314974 100644
--- a/README.md
+++ b/README.md
@@ -28,26 +28,30 @@ Run `python-lambda-local -h` to see the help.
 ```
 usage: python-lambda-local [-h] [-l LIBRARY_PATH] [-f HANDLER_FUNCTION]
                            [-t TIMEOUT] [-a ARN_STRING] [-v VERSION_NAME]
+                           [--version]
                            FILE EVENT
 
 Run AWS Lambda function written in Python on local machine.
 
 positional arguments:
-  FILE                  Lambda function file name
-  EVENT                 Event data file name.
+  FILE                  lambda function file name
+  EVENT                 event data file name
 
 optional arguments:
   -h, --help            show this help message and exit
   -l LIBRARY_PATH, --library LIBRARY_PATH
-                        Path of 3rd party libraries.
+                        path of 3rd party libraries
   -f HANDLER_FUNCTION, --function HANDLER_FUNCTION
-                        Lambda function handler name. Default: "handler".
+                        lambda function handler name, default: "handler"
   -t TIMEOUT, --timeout TIMEOUT
-                        Seconds until lambda function timeout. Default: 3
+                        seconds until lambda function timeout, default: 3
   -a ARN_STRING, --arn-string ARN_STRING
-                        arn string for function
+                        ARN string for lambda function
   -v VERSION_NAME, --version-name VERSION_NAME
-                        function version name
+                        lambda function version name
+  -e ENVIRONMENT_VARIABLES, --environment-variables ENVIRONMENT_VARIABLES
+                        path to flat json file with environment variables
+  --version             print the version of python-lambda-local and exit
 ```
 
 ### Prepare development directory
diff --git a/README.rst b/README.rst
index 1b46963..deb21a0 100644
--- a/README.rst
+++ b/README.rst
@@ -33,26 +33,28 @@ Run ``python-lambda-local -h`` to see the help.
 
     usage: python-lambda-local [-h] [-l LIBRARY_PATH] [-f HANDLER_FUNCTION]
                                [-t TIMEOUT] [-a ARN_STRING] [-v VERSION_NAME]
+                               [--version]
                                FILE EVENT
 
     Run AWS Lambda function written in Python on local machine.
 
     positional arguments:
-      FILE                  Lambda function file name
-      EVENT                 Event data file name.
+      FILE                  lambda function file name
+      EVENT                 event data file name
 
     optional arguments:
       -h, --help            show this help message and exit
       -l LIBRARY_PATH, --library LIBRARY_PATH
-                            Path of 3rd party libraries.
+                            path of 3rd party libraries
       -f HANDLER_FUNCTION, --function HANDLER_FUNCTION
-                            Lambda function handler name. Default: "handler".
+                            lambda function handler name, default: "handler"
       -t TIMEOUT, --timeout TIMEOUT
-                            Seconds until lambda function timeout. Default: 3
+                            seconds until lambda function timeout, default: 3
       -a ARN_STRING, --arn-string ARN_STRING
-                            arn string for function
+                            ARN string for lambda function
       -v VERSION_NAME, --version-name VERSION_NAME
-                            function version name
+                            lambda function version name
+      --version             print the version of python-lambda-local and exit
 
 Prepare development directory
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
diff --git a/lambda_local/__init__.py b/lambda_local/__init__.py
index 9dfd854..f56a061 100644
--- a/lambda_local/__init__.py
+++ b/lambda_local/__init__.py
@@ -9,10 +9,14 @@
 import argparse
 import sys
 from multiprocessing import Process
+import pkg_resources
 
 from .main import run
 
 
+__version__ = pkg_resources.require("python-lambda-local")[0].version
+
+
 def main():
     args = parse_args()
 
@@ -27,23 +31,31 @@ def parse_args():
     parser = argparse.ArgumentParser(description="Run AWS Lambda function" +
                                      " written in Python on local machine.")
     parser.add_argument("file", metavar="FILE", type=str,
-                        help="Lambda function file name")
+                        help="lambda function file name")
     parser.add_argument("event", metavar="EVENT", type=str,
-                        help="Event data file name.")
+                        help="event data file name")
     parser.add_argument("-l", "--library", metavar="LIBRARY_PATH",
-                        type=str, help="Path of 3rd party libraries.")
+                        type=str, help="path of 3rd party libraries")
     parser.add_argument("-f", "--function", metavar="HANDLER_FUNCTION",
                         type=str, default="handler",
-                        help="Lambda function handler name. \
-Default: \"handler\".")
+                        help="lambda function handler name, \
+default: \"handler\"")
     parser.add_argument("-t", "--timeout", metavar="TIMEOUT", type=int,
                         default=3,
-                        help="Seconds until lambda function timeout. \
-Default: 3")
+                        help="seconds until lambda function timeout, \
+default: 3")
     parser.add_argument("-a", "--arn-string", metavar="ARN_STRING", type=str,
-                        default="", help="arn string for function")
+                        default="", help="ARN string for lambda function")
     parser.add_argument("-v", "--version-name", metavar="VERSION_NAME",
-                        type=str, default="", help="function version name")
+                        type=str, default="",
+                        help="lambda function version name")
+    parser.add_argument("-e", "--environment-variables",
+                        metavar="ENVIRONMENT_VARIABLES", type=str,
+                        help="path to flat json file with environment variables")
+
+    parser.add_argument("--version", action="version",
+                        version="%(prog)s " + __version__,
+                        help="print the version of python-lambda-local and exit")
 
     return parser.parse_args()
 
diff --git a/lambda_local/environment_variables.py b/lambda_local/environment_variables.py
new file mode 100644
index 0000000..b518309
--- /dev/null
+++ b/lambda_local/environment_variables.py
@@ -0,0 +1,29 @@
+import json
+import os
+
+
+def set_environment_variables(json_file_path):
+    """
+    Read and set environment variables from a flat json file.
+
+    Bear in mind that env vars set this way and later on read using
+    `os.getenv` function will be strings since after all env vars are just
+    that - plain strings.
+
+    Json file example:
+    ```
+    {
+        "FOO": "bar",
+        "BAZ": true
+    }
+    ```
+
+    :param json_file_path: path to flat json file
+    :type json_file_path: str
+    """
+    if json_file_path:
+        with open(json_file_path) as json_file:
+            env_vars = json.loads(json_file.read())
+
+            for env_name, env_value in env_vars.items():
+                os.environ[str(env_name)] = str(env_value)
diff --git a/lambda_local/main.py b/lambda_local/main.py
index 3a46f94..95d4358 100644
--- a/lambda_local/main.py
+++ b/lambda_local/main.py
@@ -15,6 +15,7 @@
 
 from . import event
 from . import context
+from .environment_variables import set_environment_variables
 from .timeout import time_limit
 from .timeout import TimeoutException
 
@@ -31,6 +32,9 @@
 
 
 def run(args):
+    # set env vars if path to json file was given
+    set_environment_variables(args.environment_variables)
+
     e = event.read_event(args.event)
     c = context.Context(args.timeout, args.arn_string, args.version_name)
     if args.library is not None:
diff --git a/tests/environment_variables.json b/tests/environment_variables.json
new file mode 100644
index 0000000..b9b81db
--- /dev/null
+++ b/tests/environment_variables.json
@@ -0,0 +1,5 @@
+{
+    "STR_KEY": "foo",
+    "INT_KEY": 100,
+    "BOOL_KEY": false
+}
diff --git a/tests/test_environment_variables.py b/tests/test_environment_variables.py
new file mode 100644
index 0000000..6582779
--- /dev/null
+++ b/tests/test_environment_variables.py
@@ -0,0 +1,15 @@
+import os
+
+from lambda_local.environment_variables import set_environment_variables
+
+
+def test_set_environment_variables():
+    os.getenv('STR_KEY') is None
+    os.getenv('INT_KEY') is None
+    os.getenv('BOOL_KEY') is None
+
+    set_environment_variables('tests/environment_variables.json')
+
+    assert os.getenv('STR_KEY') == 'foo'
+    assert os.getenv('INT_KEY') == '100'
+    assert os.getenv('BOOL_KEY') == 'False'