In this study, the effect of chlorogenic acid obtained as an antioxidant from Green Coffee Extract (
GCE
) on the shelf life of Hazelnut Paste (
HP
) was investigated at 4, 25, and 40 °C for 3 months. The analysis of variance showed that the effect of
AR
(Additive Ratio) ×
T
(Temperature) ×
t
(Storage Time) interaction on Peroxide Number (
PV
), tocopherols, and phenolics (
TPC
) of
GCE-HP
mixtures was found to be significant (
P
<
0.05
).
ARxt
factor on Hunter L*, a*, and b* color values,
DPPH
-radical scavenging activity and antioxidant activity (
AA
),
Txt
factor on oleic/linoleic acid ratio (
O/L
), and
ARxT
and
ARxt
interactions on free fatty acid were more effective (
P
<
0.05
). Regression equations of
O/L
,
PV
,
AA
, and
TPC
can be used to calculate the shelf life of
HP
due to high
R
2
values (87.14–94.46%). In addition, according to the
O/L
regression equation, the shelf life of the
HP
control samples was 28 days at 22 °C, increased to 60 days at 0.5%-
GCE
and 90 days at 25.68 °C at 0.75%-
GCE
(
R
2
= 87.14%,
P
<
0.001
).
GCE
(0.5–0.75%) was a promising antioxidant in increasing the shelf life of HP.