The Milwaukee Brewers have the highest K/9 by a team in a season, with 12.03 per nine innings in 1884.

	TEAM	K/9	SEASON	G	W%	W	L	GS	ERA	SO	CG	SHO	SV	IP	H	ER	R	HR	BB	HBP	IBB	TBF	WP	BB/9	K/BB	HR/9	K%	BB%	WHIP	BABIP	RA	H/9
1	Brewers	12.03	1884	12	.667	8	4	12	2.25	139	12		0	104.0	49	26	34	1	13			386	7	1.13	10.69	0.09	36.0	3.4	0.60		2.94	4.24
2	Reds	10.98	2020	60	.517	31	29	60	3.84	615	3	2	9	504.0	401	215	243	67	213	29	6	2,125	23	3.80	2.89	1.20	28.9	10.0	1.22	.278	4.34	7.16
3	Brewers	10.68	2020	60	.483	29	31	60	4.16	614	1	0	14	517.1	446	239	264	67	189	35	1	2,186	21	3.29	3.25	1.17	28.1	8.6	1.23	.296	4.59	7.76
4	Astros	10.44	2018	162	.636	103	59	162	3.11	1,687	2	2	46	1455.0	1,164	503	534	152	435	66	4	5,913	67	2.69	3.88	0.94	28.5	7.4	1.10	.283	3.30	7.20
5	Indians	10.43	2020	60	.583	35	25	60	3.29	621	1	0	20	536.0	440	196	209	68	157	27	8	2,176	20	2.64	3.96	1.14	28.5	7.2	1.11	.285	3.51	7.39
6	Astros	10.28	2019	162	.660	107	55	162	3.66	1,671	2	1	47	1462.1	1,205	595	640	230	448	41	0	5,995	41	2.76	3.73	1.42	27.9	7.5	1.13	.270	3.94	7.42
7	White Sox	10.18	2021	162	.574	93	69	162	3.73	1,588	4	3	43	1403.1	1,205	581	636	182	485	51	16	5,861	84	3.11	3.27	1.17	27.1	8.3	1.20	.288	4.08	7.73
8	Brewers	10.14	2021	162	.586	95	67	162	3.50	1,618	2	1	44	1436.0	1,156	558	623	168	537	77	19	5,990	60	3.37	3.01	1.05	27.0	9.0	1.18	.275	3.90	7.25
9	Yankees	10.10	2018	162	.617	100	62	162	3.78	1,634	2	2	49	1456.1	1,311	611	669	177	494	58	9	6,141	73	3.05	3.31	1.09	26.6	8.0	1.24	.300	4.13	8.10
10	Indians	10.08	2017	162	.630	102	60	162	3.30	1,614	7	3	37	1440.2	1,267	529	564	163	406	45	15	5,866	48	2.54	3.98	1.02	27.5	6.9	1.16	.303	3.52	7.92
11	Mets	10.06	2020	60	.433	26	34	60	4.98	574	0	0	11	513.1	511	284	308	81	219	29	7	2,262	24	3.84	2.62	1.42	25.4	9.7	1.42	.316	5.40	8.96
12	Red Sox	9.99	2019	162	.519	84	78	162	4.70	1,633	1	1	33	1471.0	1,423	768	828	215	605	76	22	6,399	81	3.70	2.70	1.32	25.5	9.5	1.38	.312	5.07	8.71
13	Astros	9.91	2017	162	.623	101	61	162	4.12	1,593	1	0	45	1446.0	1,314	662	700	192	522	70	17	6,111	86	3.25	3.05	1.20	26.1	8.5	1.27	.300	4.36	8.18
14	Dodgers	9.91	2021	162	.654	106	56	162	3.01	1,599	1	0	56	1452.0	1,107	486	561	161	486	63	43	5,948	52	3.01	3.29	1.00	26.9	8.2	1.10	.260	3.48	6.86
15	Rays	9.90	2019	162	.593	96	66	162	3.65	1,621	0	0	46	1474.1	1,274	598	656	181	453	60	27	6,086	59	2.77	3.58	1.10	26.6	7.4	1.17	.290	4.00	7.78
16	Yankees	9.84	2021	162	.568	92	70	162	3.74	1,569	3	2	47	1435.1	1,243	596	669	196	492	56	10	5,999	85	3.08	3.19	1.23	26.2	8.2	1.21	.284	4.19	7.79
17	Mets	9.79	2022	162	.623	101	61	162	3.57	1,565	0	0	41	1438.2	1,274	570	606	169	428	71	13	5,950	35	2.68	3.66	1.06	26.3	7.2	1.18	.297	3.79	7.97
18	Padres	9.77	2020	60	.617	37	23	60	3.86	565	1	1	13	520.1	456	223	241	70	170	22	2	2,160	19	2.94	3.32	1.21	26.2	7.9	1.20	.290	4.17	7.89
19	Reds	9.71	2019	162	.463	75	87	162	4.18	1,552	0	0	46	1438.0	1,270	668	711	214	536	58	31	6,057	35	3.35	2.90	1.34	25.6	8.8	1.26	.286	4.45	7.95
20	Yankees	9.69	2017	162	.562	91	71	162	3.72	1,560	2	1	36	1448.2	1,248	599	660	192	504	53	18	6,078	83	3.13	3.10	1.19	25.7	8.3	1.21	.280	4.10	7.75
21	Red Sox	9.68	2021	162	.568	92	70	162	4.26	1,527	0	0	49	1419.0	1,409	671	749	176	546	79	31	6,147	63	3.46	2.80	1.12	24.8	8.9	1.38	.323	4.75	8.94
22	Braves	9.68	2024	162	.549	89	73	162	3.49	1,553	2	1	40	1443.1	1,277	559	607	150	449	68	18	5,978	34	2.80	3.46	0.94	26.0	7.5	1.20	.300	3.78	7.96
23	Twins	9.67	2023	162	.537	87	75	162	3.87	1,560	2	2	38	1451.1	1,294	624	659	194	443	63	16	6,028	51	2.75	3.52	1.20	25.9	7.3	1.20	.292	4.09	8.02
24	Braves	9.66	2022	162	.623	101	61	162	3.46	1,554	1	1	55	1448.0	1,224	556	609	148	500	62	21	6,031	55	3.11	3.11	0.92	25.8	8.3	1.19	.286	3.79	7.61
25	Dodgers	9.65	2017	162	.642	104	58	162	3.38	1,549	2	0	51	1444.2	1,226	543	580	184	442	40	33	5,925	40	2.75	3.50	1.15	26.1	7.5	1.15	.281	3.61	7.64