Haruka Kaji (加治 遥, Kaji Haruka, born 25 September 1994) is a Japanese professional tennis player.

She has career-high WTA rankings of 213 in singles, achieved on 25 September 2023, and 131 in doubles, set on 3 February 2020.

Kaji won her biggest ITF title to date at the 2019 Challenger de Granby, in the doubles tournament, partnering Ingrid Neel.

Result	W–L	Date	Tournament	Tier	Surface	Opponent	Score
Win	1–0	Dec 2015	ITF Hong Kong	W10	Hard	Tori Kinard	6–1, 3–6, 2–2 ret.
Loss	1–1	Oct 2016	ITF Tarakan, Indonesia	W10	Hard (i)	Kaitlyn Christian	7–5, 3–6, 2–6
Win	2–1	Jun 2017	Kofu Women's Cup, Japan	W25	Hard	Olivia Tjandramulia	6–1, 6–3
Loss	2–2	Jun 2017	ITF Taipei, Taiwan	W15	Hard	Lee Pei-chi	6–3, 5–7, 2–6
Win	3–2	Aug 2017	ITF Nonthaburi, Thailand	W15	Hard	Lee Hua-chen	6–4, 6–1
Win	4–2	Dec 2017	ITF Hong Kong	W15	Hard	Hiroko Kuwata	4–6, 6–2, 7–6(4)
Loss	4–3	Aug 2019	ITF Tsukuba, Japan	W25	Hard (i)	Akiko Omae	6–3, 6–7(5), 3–6
Loss	4–4	Sep 2019	ITF Kyoto, Japan	W25	Hard (i)	Lee Ya-hsuan	3–6, 4–6
Win	5–4	Oct 2022	Noto International, Japan	W25	Carpet	Momoko Kobori	3–6, 6–3, 6–3
Win	6–4	Oct 2022	ITF Hamamatsu, Japan	W25	Carpet	Ikumi Yamazaki	1–1 ret.
Loss	6–5	May 2023	ITF Karuizawa, Japan	W25	Grass	Wang Yafan	0–6, 1–6
Loss	6–6	Aug 2024	ITF Roehampton, United Kingdom	W35	Hard	Sonay Kartal	3–6, 1–6
Loss	6–7	Aug 2024	ITF Ourense, Spain	W50	Hard	Alina Charaeva	6–7(7), 1–6

Result	W–L	Date	Tournament	Tier	Surface	Partner	Opponents	Score
Win	1–0	Mar 2015	ITF Kofu, Japan	W10	Hard	Aiko Yoshitomi	Rika Fujiwara Akari Inoue	6–2, 6–3
Loss	1–1	Dec 2015	ITF Hong Kong	W10	Hard	Mana Ayukawa	Emma Laine Yukina Saigo	w/o
Win	2–1	Jun 2016	ITF Kaohsiung, Taiwan	W10	Hard	Erina Hayashi	Chen Pei-hsuan Wu Fang-hsien	6–4, 3–6, [10–7]
Win	3–1	Jun 2018	ITF Singapore	W25	Hard	Akiko Omae	Han Na-lae Lee So-ra	7–5, 6–2
Win	4–1	Feb 2019	ITF Jodhpur, India	W25	Hard	Mana Ayukawa	Eri Hozumi Miyabi Inoue	7–6(4), 4–6, [10–5]
Loss	4–2	May 2019	ITF Nonthaburi, Thailand	W25	Hard	Risa Ozaki	Aleksandrina Naydenova İpek Soylu	1–6, 3–6
Win	5–2	Jun 2019	ITF Jakarta, Indonesia	W25	Hard	Junri Namigata	Beatrice Gumulya Jessy Rompies	6–2, 4–6, [10–7]
Loss	5–3	Jul 2019	ITF Saskatoon, Canada	W25	Hard	Momoko Kobori	Hsu Chieh-yu Marcela Zacarías	3–6, 2–6
Win	6–3	Jul 2019	Challenger de Granby, Canada	W80	Hard	Junri Namigata	Quinn Gleason Ingrid Neel	7–6(5), 5–7, [10–8]
Loss	6–4	Nov 2019	ITF Tokyo Open, Japan	W100	Hard	Junri Namigata	Choi Ji-hee Han Na-lae	3–6, 3–6

• Haruka Kaji at the Women's Tennis Association
• Haruka Kaji at the International Tennis Federation