Index: Mk/Uses/python.mk
===================================================================
--- Mk/Uses/python.mk
+++ Mk/Uses/python.mk
@@ -468,6 +468,10 @@
 EXPIRATION_DATE?=	2020-12-31
 .endif
 
+.if ${PYTHON_REL} < 3700
+NOT_REPRODUCIBLE=	yes
+.endif
+
 .if !defined(PYTHONBASE)
 PYTHONBASE!=	(${PYTHON_CMD} -c 'import sys; print(sys.prefix)' \
 			2> /dev/null || ${ECHO_CMD} ${LOCALBASE}) | ${TAIL} -1
Index: Mk/bsd.port.mk
===================================================================
--- Mk/bsd.port.mk
+++ Mk/bsd.port.mk
@@ -2046,7 +2046,15 @@
 CHECKSUM_ALGORITHMS?= sha256
 
 DISTINFO_FILE?=		${MASTERDIR}/distinfo
+_TIMESTAMP=			0
+.if !defined(NOT_REPRODUCIBLE) && exists(${DISTINFO_FILE})
+.if !defined(TIMESTAMP_CACHE) || empty(_TIMESTAMP_CACHE)
+_TIMESTAMP_CACHE!=	${AWK} -F= -v ts=0 '/^TIMESTAMP/ { gsub(" ", "", $$2); ts=$$2 } END { print ts}' ${DISTINFO_FILE}
+.endif
+_TIMESTAMP=${_TIMESTAMP_CACHE}
+.endif
 
+
 MAKE_FLAGS?=	-f
 MAKEFILE?=		Makefile
 MAKE_CMD?=		${BSDMAKE}
@@ -2058,6 +2066,10 @@
 			CXX="${CXX}" CXXFLAGS="${CXXFLAGS}" \
 			MANPREFIX="${MANPREFIX}"
 
+.if ${_TIMESTAMP} != 0
+MAKE_ENV+=	SOURCE_DATE_EPOCH="${_TIMESTAMP}"
+.endif
+
 # Add -fno-strict-aliasing to CFLAGS with optimization level -O2 or higher.
 # gcc 4.x enable strict aliasing optimization with -O2 which is known to break
 # a lot of ports.
@@ -3428,6 +3440,9 @@
 
 .if !target(do-package)
 PKG_CREATE_ARGS=	-r ${STAGEDIR}
+.if ${_TIMESTAMP} != 0
+PKG_CREATE_ARGS+=	-t ${_TIMESTAMP}
+.endif
 .  if defined(PKG_CREATE_VERBOSE)
 PKG_CREATE_ARGS+=	-v
 .  endif