diff --git a/.evergreen/config.yml b/.evergreen/config.yml
index 6c0f99d57..edec4bd69 100644
--- a/.evergreen/config.yml
+++ b/.evergreen/config.yml
@@ -334,7 +334,7 @@ functions:
         working_dir: "src"
         script: |
           ${PREPARE_SHELL}
-          PYTHON_BINARY=${PYTHON_BINARY} AUTH=${AUTH} SSL=${SSL} MONGODB_URI="${MONGODB_URI}" sh ${PROJECT_DIRECTORY}/.evergreen/run-tests.sh
+          PYTHON_BINARY=${PYTHON_BINARY} C_EXTENSIONS=${C_EXTENSIONS} AUTH=${AUTH} SSL=${SSL} MONGODB_URI="${MONGODB_URI}" sh ${PROJECT_DIRECTORY}/.evergreen/run-tests.sh
 
   "cleanup":
     - command: shell.exec
@@ -822,6 +822,13 @@ axes:
         display_name: "Jython 2.7"
         variables:
            PYTHON_BINARY: "/opt/python/jython2.7/bin/jython"
+  - id: c-extensions
+    display_name: "C Extensions"
+    values:
+      - id: "without-c-extensions"
+        display_name: "Without C Extensions"
+        variables:
+           C_EXTENSIONS: "--no_ext"
   #- id: windows-vs2008-python-version
   #  display_name: "Windows Visual Studio 2008 Python"
   #  values:
@@ -1017,6 +1024,36 @@ buildvariants:
      - name: "test-2.4-sharded_cluster"
      - name: "test-2.4-standalone"
 
+- matrix_name: "tests-python-version-ubuntu1604-without-c-extensions"
+  matrix_spec: {"python-version": "*", "c-extensions": "without-c-extensions", auth: "noauth", ssl: "nossl" }
+  exclude_spec:
+   # These interpreters are always tested without extensions.
+   - python-version: ["pypy", "pypy3", "jython2.5", "jython2.7"]
+     c-extensions: "*"
+     auth: "*"
+     ssl: "*"
+  display_name: "${c-extensions} ${python-version} Ubuntu 16.04 (x86_64) ${auth} ${ssl}"
+  run_on: ubuntu1604-test
+  tasks:
+     - name: "test-latest-replica_set"
+     - name: "test-latest-sharded_cluster"
+     - name: "test-latest-standalone"
+     - name: "test-3.4-replica_set"
+     - name: "test-3.4-sharded_cluster"
+     - name: "test-3.4-standalone"
+     - name: "test-3.2-replica_set"
+     - name: "test-3.2-sharded_cluster"
+     - name: "test-3.2-standalone"
+     - name: "test-3.0-replica_set"
+     - name: "test-3.0-sharded_cluster"
+     - name: "test-3.0-standalone"
+     - name: "test-2.6-replica_set"
+     - name: "test-2.6-sharded_cluster"
+     - name: "test-2.6-standalone"
+     - name: "test-2.4-replica_set"
+     - name: "test-2.4-sharded_cluster"
+     - name: "test-2.4-standalone"
+
 # TODO: Figure out SSL on Windows.
 
 # Test Python 2.6, 2.7, and 3.2 against all versions on MongoDB >= 2.4
diff --git a/.evergreen/run-tests.sh b/.evergreen/run-tests.sh
index f8fb0b0fa..f1708f2b5 100755
--- a/.evergreen/run-tests.sh
+++ b/.evergreen/run-tests.sh
@@ -13,6 +13,7 @@ AUTH=${AUTH:-noauth}
 SSL=${SSL:-nossl}
 MONGODB_URI=${MONGODB_URI:-}
 PYTHON_BINARY=${PYTHON_BINARY:-}
+C_EXTENSIONS=${C_EXTENSIONS:-}
 
 
 if [ "$AUTH" != "noauth" ]; then
@@ -74,4 +75,4 @@ $PYTHON -c 'import sys; print(sys.version)'
 # files in the xunit-results/ directory.
 
 $PYTHON setup.py clean
-$PYTHON $EXTRA_ARGS setup.py $TEST_CMD $TEST_VERBOSITY
+$PYTHON $EXTRA_ARGS setup.py $C_EXTENSIONS $TEST_CMD $TEST_VERBOSITY