Ted Williams has the most bases on balls in a month, with 50 bases on balls in August 1941.

	NAME	BB	MONTH	G	AB	R	H	2B	3B	HR	RBI	HBP	SO	SB	CS	PA	TB	XBH	SH	SF	IBB	GIDP	AVG	OBP	SLG	OPS
1	Ted Williams T. Williams	50	August 1941	35	107	31	43	4	2	10	26	0	8	0		157	81	16	0			2	.402	.592	.757	1.349
2	Barry Bonds B. Bonds	46	June 2004	27	67	23	22	4	0	6	14	3	6	0	0	116	44	10	0	0	23	0	.328	.612	.657	1.269
3	Ted Williams T. Williams	45	July 1954	33	104	31	40	7	0	11	29	0	9	0	0	152	80	18	0	3		2	.385	.559	.769	1.328
4	Max Bishop M. Bishop	44	July 1930	31	102	28	26	4	2	2	14	1	14	0		149	40	8	2				.255	.483	.392	.875
5	Barry Bonds B. Bonds	43	September 2002	25	69	20	25	4	0	6	22	2	7	3	0	114	47	10	0	0	15	1	.362	.614	.681	1.295
6	Babe Ruth B. Ruth	43	July 1920	34	100	45	44	10	2	13	33	1	19	5		147	97	25	3				.440	.611	.970	1.581
7	Mickey Mantle M. Mantle	42	July 1957	30	95	31	28	1	2	7	20	0	13	5	2	139	54	10	0	2	9	2	.295	.504	.568	1.072
8	Jack Clark J. Clark	41	July 1987	25	71	17	19	3	0	6	19	0	28	1	1	113	40	9	0	1	6	0	.268	.531	.563	1.094
9	Barry Bonds B. Bonds	40	September 2004	25	63	22	22	4	2	7	13	4	12	0	0	108	51	13	0	1	23	1	.349	.611	.810	1.421
10	Barry Bonds B. Bonds	40	June 2002	26	70	19	26	4	1	7	17	1	8	1	0	111	53	12	0	0	17	1	.371	.604	.757	1.361
11	Ted Williams T. Williams	40	August 1954	30	99	25	33	6	0	7	24	0	8	0	0	139	60	13	0	0		3	.333	.525	.606	1.131
12	Barry Bonds B. Bonds	39	April 2004	23	53	21	25	5	0	10	22	0	6	2	0	92	60	15	0	0	18	2	.472	.696	1.132	1.828
13	Ralph Kiner R. Kiner	39	August 1951	33	104	28	30	5	1	11	24	0	11	1	0	143	70	17	0			3	.288	.483	.673	1.156
14	Roy Cullenbine R. Cullenbine	39	July 1947	31	104	30	27	5	0	6	12	0	11	2		144	50	11	1			3	.260	.462	.481	.942
15	Lou Gehrig L. Gehrig	39	August 1935	35	126	38	48	11	2	10	48	1	11	3		166	93	23	0				.381	.530	.738	1.268
16	Joey Votto J. Votto	38	August 2015	28	86	20	27	8	0	6	14	0	25	2	1	124	53	14	0	0	4	2	.314	.524	.616	1.140
17	Barry Bonds B. Bonds	38	August 2004	27	70	27	29	6	1	11	27	0	7	2	1	109	70	18	0	1	15	0	.414	.615	1.000	1.615
18	Eddie Stanky E. Stanky	38	August 1950	30	95	28	29	4	2	0	11	3	9	2		136	37	6	0			1	.305	.515	.389	.904
19	Eddie Stanky E. Stanky	38	September 1945	32	113	26	28	7	0	0	10	1	12	1		159	35	7	7			0	.248	.441	.310	.751
20	Bryce Harper B. Harper	37	April 2018	27	83	22	20	1	0	8	17	0	21	3	0	122	45	9	0	2	8	0	.241	.467	.542	1.009
21	Barry Bonds B. Bonds	37	August 2002	27	76	24	34	6	0	11	25	1	7	1	1	116	73	17	0	2	11	1	.447	.621	.961	1.581
22	Babe Ruth B. Ruth	37	August 1932	29	92	30	37	4	1	9	26	2	13	0		131	70	14	0				.402	.580	.761	1.341
23	Babe Ruth B. Ruth	37	June 1930	28	97	43	38	6	0	15	35	0	12	2		137	89	21	3				.392	.560	.918	1.477
24	Max Bishop M. Bishop	37	May 1930	28	88	29	19	5	0	6	13	3	10	0		130	42	11	2				.216	.461	.477	.938
25	Mel Ott M. Ott	37	June 1929	33	121	35	41	12	0	11	47	2	7	2		165	86	23	5				.339	.500	.711	1.211