diff --git a/CMakeLists.txt b/CMakeLists.txt
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -30,6 +30,9 @@
 		"Select the configuration for the build" FORCE)
 endif()
 
+# Find the python interpreter. This is required for several targets.
+find_package(PythonInterp 3.4 REQUIRED)
+
 # Add the magic targets `check` and `check-all`
 add_custom_target(check-all)
 add_custom_target(check)
diff --git a/contrib/devtools/CMakeLists.txt b/contrib/devtools/CMakeLists.txt
--- a/contrib/devtools/CMakeLists.txt
+++ b/contrib/devtools/CMakeLists.txt
@@ -2,11 +2,11 @@
 
 add_custom_target(check-devtools)
 
-set(DEVTOOLS_TESTS
+set(DEVTOOLS_TESTS_PYTHON
   ./chainparams/test_make_chainparams.py
 )
 
-foreach(TEST ${DEVTOOLS_TESTS})
+foreach(TEST ${DEVTOOLS_TESTS_PYTHON})
   get_filename_component(TESTNAME ${TEST} NAME)
   get_filename_component(TESTPATH ${TEST} ABSOLUTE ${CMAKE_CURRENT_SOURCE_DIR})
   get_filename_component(WORKDIR ${TESTPATH} DIRECTORY)
@@ -14,6 +14,7 @@
     WORKING_DIRECTORY
       ${WORKDIR}
     COMMAND
+      "${PYTHON_EXECUTABLE}"
       "./${TESTNAME}"
   )
   add_dependencies(check-devtools "check-devtools-${TESTNAME}")
diff --git a/src/bench/CMakeLists.txt b/src/bench/CMakeLists.txt
--- a/src/bench/CMakeLists.txt
+++ b/src/bench/CMakeLists.txt
@@ -9,7 +9,6 @@
 # Process raw files.
 file(MAKE_DIRECTORY "${CMAKE_CURRENT_BINARY_DIR}/data")
 
-find_program(PYTHON python3)
 foreach(_raw_file ${BENCH_DATA_RAW_FILES})
 	string(APPEND
 		_generated_header_output
@@ -21,8 +20,8 @@
 
 	add_custom_command(
 		OUTPUT "${_generated_header_output}"
-		COMMAND "${PYTHON}"
-		ARGS
+		COMMAND 
+			"${PYTHON_EXECUTABLE}"
 			"data/convert-raw-to-header.py"
 			"${_test_name}"
 			"${_raw_file}" > "${_generated_header_output}"
diff --git a/src/test/CMakeLists.txt b/src/test/CMakeLists.txt
--- a/src/test/CMakeLists.txt
+++ b/src/test/CMakeLists.txt
@@ -5,7 +5,6 @@
 # Process json files.
 file(MAKE_DIRECTORY "${CMAKE_CURRENT_BINARY_DIR}/data")
 
-find_program(PYTHON python3)
 function(gen_json_header NAME)
 	set(HEADERS "")
 	foreach(f ${ARGN})
@@ -14,8 +13,8 @@
 		# Get the proper name for the test variable.
 		get_filename_component(TEST_NAME ${f} NAME_WE)
 		add_custom_command(OUTPUT ${h}
-			COMMAND ${PYTHON}
-			ARGS
+			COMMAND
+				"${PYTHON_EXECUTABLE}"
 				"${CMAKE_CURRENT_SOURCE_DIR}/data/generate_header.py"
 				"${TEST_NAME}"
 				"${CMAKE_CURRENT_SOURCE_DIR}/${f}" > ${h}
diff --git a/test/CMakeLists.txt b/test/CMakeLists.txt
--- a/test/CMakeLists.txt
+++ b/test/CMakeLists.txt
@@ -56,6 +56,7 @@
 
 add_custom_target(check-functional
 	COMMAND
+		"${PYTHON_EXECUTABLE}"
 		./functional/test_runner.py
 	DEPENDS
 		../src/bitcoind
@@ -71,6 +72,7 @@
 		COMMAND
 			${CMAKE_COMMAND} -E echo "Running test/util/bitcoin-util-test.py..."
 		COMMAND
+			"${PYTHON_EXECUTABLE}"
 			./util/bitcoin-util-test.py
 		DEPENDS
 			../src/bitcoin-tx
@@ -84,6 +86,7 @@
 	COMMAND
 		${CMAKE_COMMAND} -E echo "Running test/util/rpcauth-test.py..."
 	COMMAND
+		"${PYTHON_EXECUTABLE}"
 		./util/rpcauth-test.py
 	DEPENDS
 		${CMAKE_CURRENT_BINARY_DIR}/util/rpcauth-test.py