Exhibit 99.3

02BV Using a b l a c k i n k pen, mark your votes with an X as shown in this example.Please do not write outside the designated areas. 03PPPB ++ P r o p o s a l s — T h e B o a r d o f D i r e c t o r s r e c o m m e n d a v o t e F O R P r o p o s a l s 1 - 2 . A 1. To approve the Agreement and Plan of Merger, dated September20, 2022, by and among, Southern Missouri Bancorp, Inc.,Southern Missouri Acquisition VI Corp., and Citizens BancsharesCo. pursuant to which Citizens Bancshares Co. will merge with andinto Southern Missouri Acquisition VI Corp., followed by a mergerof Southern Missouri Acquisition VI Corp. with and into SouthernMissouri Bancorp, Inc. (the “Merger Agreement Proposal”) 2. To approve the Adjournment of the Special Meeting, if necessaryor appropriate, to solicit additional proxies in favor of the MergerAgreement Proposal (the “Citizens Adjournment Proposal”) F o r A g a i n s t A b s t a i n Please sign exactly as name(s) appears hereon. Joint owners should each sign. When signing as attorney, executor, administrator, corporate officer, trustee, guardian, or custodian, please give full title.Signature 1 — Please keep signature within the box.Signature 2 — Please keep signature within the box.Date (mm/dd/yyyy) — Please print date below. A u t h o r i z e d S i g n a t u r e s — T h i s s e c t i o n m u s t b e c o m p l e t e d f o r y o u r v o t e t o c o u n t . P l e a s e d a t e a n d s i g n b e l o w . B q I F V O T I N G B Y M A I L , S I G N , D E T A C H A N D R E T U R N T H E B O T T O M P O R T I O N I N T H E E N C L O S E D E N V E L O P E . q S p e c i a l M e e t i n g P r o x y C a r d F o r A g a i n s t A b s t a i n 000004 MR A SAMPLEDESIGNATION (IF ANY)ADD 1ADD 2ADD 3ADD 4ADD 5ADD 6ENDORSEMENT_LINE______________ SACKPACK_____________1234 5678 9012 345 MMMMMMMMM MMMMMMMMMMMMMMM 556771MR A SAMPLE (THIS AREA IS SET UP TO ACCOMMODATE140 CHARACTERS) MR A SAMPLE AND MR A SAMPLE ANDMR A SAMPLE AND MR A SAMPLE AND MR A SAMPLE ANDMR A SAMPLE AND MR A SAMPLE AND MR A SAMPLE AND C 1234567890 JNTC123456789 MMMMMMMMMMMMM MMMMMMM 000000000.000000 ext000000000.000000 ext000000000.000000 ext000000000.000000 ext000000000.000000 ext000000000.000000 extIf no electronic voting, delete QR code and control #∆≈ You may vote online or by phone instead of mailing this card. O n l i n e Go to w w w . e n v i s i o n r e p o r t s . c o m / C I B C orscan the QR code — login details arelocated in the shaded bar below. S a v e p a p e r , t i m e a n d m o n e y ! S i g n u p f o r e l e c t r o n i c d e l i v e r y a t w w w . e n v i s i o n r e p o r t s . c o m / C I B C P h o n e Call toll free 1-800-652-VOTE (8683) withinthe USA, US territories and Canada V o t e s s u b m i t t e d e l e c t r o n i c a l l y m u s t b e r e c e i v e d b y 1 : 0 0 a m , C e n t r a l T i m e , o n [ . ] , 2 0 2 [ . ] . Y o u r v o t e m a t t e r s – h e r e ’ s h o w t o v o t e !

S m a l l s t e p s m a k e a n i m p a c t . Help the environment by consenting to receive electronic delivery, sign up at www.envisionreports.com/CIBCq I F V O T I N G B Y M A I L , S I G N , D E T A C H A N D R E T U R N T H E B O T T O M P O R T I O N I N T H E E N C L O S E D E N V E L O P E . q C h a n g e o f A d d r e s s —Please print new address below. C o m m e n t s — Please print your comments below. N o n - V o t i n g I t e m s C ++ T H I S P R O X Y I S S O L I C I T E D O N B E H A L F O F T H E B O A R D O F D I R E C T O R S O F C I T I Z E N S B A N C S H A R E S C O . The undersigned acknowledges receipt of the Notice of Special Meeting of Shareholders and the accompanying Joint Proxy Statement/Prospectus, each dated[________], 202[.], regarding the Special Meeting of Shareholders of Citizens Bancshares Co. to be held on [_________], 202[.], and any adjournments orpostponements thereof. The undersigned hereby revokes all prior proxies and hereby appoints Don Walsworth, Sr. and Roger Arwood, and each of them, withor without the other, with full power of substitution and re-substitution, as proxies of the undersigned to represent the undersigned and to vote all sharesof common stock of Citizens Bancshares Co. that the undersigned would be entitled to vote if personally present at the Special Meeting and any adjournmentsor postponements thereof. T h i s p r o x y , w h e n p r o p e r l y e x e c u t e d , w i l l b e v o t e d i n t h e m a n n e r d i r e c t e d h e r e i n . I f t h i s p r o x y i s p r o p e r l y e x e c u t e d a n d r e t u r n e d b u t n o d i r e c t i o n i s g i v e n , t h i s p r o x y w i l l b e v o t e d : ( i ) “ F O R ” a p p r o v a l o f t h e M e r g e r A g r e e m e n t P r o p o s a l ( a s d e f i n e d o n t h e r e v e r s e s i d e o f h e r e ) , ( i i ) “ F O R ” a p p r o v a l o f t h e C i t i z e n s A d j o u r n m e n t P r o p o s a l ( a s d e f i n e d o n t h e r e v e r s e s i d e o f h e r e ) , a n d ( i i i ) i n t h e d i s c r e t i o n o f t h e p r o x y h o l d e r s o n a n y o t h e r m a t t e r t h a t m a y p r o p e r l y c o m e b e f o r e t h e S p e c i a l M e e t i n g . I f y o u v o t e t o “ A B S T A I N ” r e g a r d i n g t h e M e r g e r A g r e e m e n t P r o p o s a l o r t h e C i t i z e n s A d j o u r n m e n t P r o p o s a l , i t w i l l h a v e t h e s a m e e f f e c t a s a n “ A G A I N S T ” v o t e w i t h r e s p e c t t o s u c h p r o p o s a l . Y o u m a y r e v o k e t h i s p r o x y a t a n y t i m e p r i o r t o t h e v o t e o f t h e s h a r e h o l d e r s a t t h e S p e c i a l M e e t i n g a s p r o v i d e d i n t h e J o i n t P r o x y S t a t e m e n t / P r o s p e c t u s . I m p o r t a n t n o t i c e r e g a r d i n g t h e I n t e r n e t a v a i l a b i l i t y o f p r o x y m a t e r i a l s f o r t h e A n n u a l M e e t i n g o f S h a r e h o l d e r s . T h e m a t e r i a l i s a v a i l a b l e a t : w w w . e n v i s i o n r e p o r t s . c o m / C I B C