diff --git a/eclass/python-any-r1.eclass b/eclass/python-any-r1.eclass
index 0f641a8a64431..c00cc3a3e09a7 100644
--- a/eclass/python-any-r1.eclass
+++ b/eclass/python-any-r1.eclass
@@ -75,6 +75,9 @@ if [[ ! ${_PYTHON_ANY_R1} ]]; then
 if ! declare -p PYTHON_COMPAT &>/dev/null; then
 	die 'PYTHON_COMPAT not declared.'
 fi
+if [[ $(declare -p PYTHON_COMPAT) != "declare -a"* ]]; then
+	die 'PYTHON_COMPAT must be an array.'
+fi
 
 # @ECLASS-VARIABLE: PYTHON_REQ_USE
 # @DEFAULT_UNSET
diff --git a/eclass/python-r1.eclass b/eclass/python-r1.eclass
index 7113cfa95d164..d3b4f1d500f72 100644
--- a/eclass/python-r1.eclass
+++ b/eclass/python-r1.eclass
@@ -84,6 +84,9 @@ inherit multibuild python-utils-r1
 if ! declare -p PYTHON_COMPAT &>/dev/null; then
 	die 'PYTHON_COMPAT not declared.'
 fi
+if [[ $(declare -p PYTHON_COMPAT) != "declare -a"* ]]; then
+	die 'PYTHON_COMPAT must be an array.'
+fi
 
 # @ECLASS-VARIABLE: PYTHON_COMPAT_OVERRIDE
 # @INTERNAL
diff --git a/eclass/python-single-r1.eclass b/eclass/python-single-r1.eclass
index 132d40753b376..1c2728514beaf 100644
--- a/eclass/python-single-r1.eclass
+++ b/eclass/python-single-r1.eclass
@@ -98,6 +98,9 @@ if [[ ! ${_PYTHON_SINGLE_R1} ]]; then
 if ! declare -p PYTHON_COMPAT &>/dev/null; then
 	die 'PYTHON_COMPAT not declared.'
 fi
+if [[ $(declare -p PYTHON_COMPAT) != "declare -a"* ]]; then
+	die 'PYTHON_COMPAT must be an array.'
+fi
 
 # @ECLASS-VARIABLE: PYTHON_REQ_USE
 # @DEFAULT_UNSET